October 23, 2007 | By RICHARD A. OPPEL Jr.

BAGHDAD, Oct. 22 — Deadly raids into Turkey by Kurdish militants holed up in northern Iraq are the focus of urgent diplomacy, with Turkey threatening invasion of Iraq and the United States begging for restraint while expressing solidarity with Turkish anger.

Yet out of the public eye, a chillingly similar battle has been under way on the Iraqi border with Iran. Kurdish guerrillas ambush and kill Iranian forces and retreat to their hide-outs in Iraq. The Americans offer Iran little sympathy. Tehran even says Washington aids the Iranian guerrillas, a charge the United States denies. True or not, that conflict, like the Turkish one, has explosive potential.

Salih Shevger, an Iranian Kurdish guerrilla, was interviewed recently as he lay flat on a slab of rock atop a 10,000-foot mountain on the Iran-Iraq border, with binoculars pressed to his face as he kept watch on Iranian military outposts perched on peaks about four miles away.

He and his comrades recounted how they ambushed an Iranian patrol between the bases a few days before, killing three soldiers and capturing another. “They were sitting and talking on top of a hill, and we approached, hiding ourselves, and fired on them from two sides,” said Bayram Gabar, who commanded the raid, and who like all the fighters here uses a nom de guerre.

The guerrillas from the Party for Free Life in Kurdistan, or P.J.A.K., have been waging a deadly insurgency in Iran and they are an offshoot of the Kurdistan Workers’ Party, known as the P.K.K., the Kurdish guerrillas who fight Turkey.

Like the P.K.K., the Iranian Kurds control much of the craggy, boulder-strewn frontier and routinely ambush patrols on the other side. But while the Americans call the P.K.K. terrorists, guerrilla commanders say P.J.A.K. has had “direct or indirect discussions” with American officials. They would not divulge any details of the discussions or the level of the officials involved, but they noted that the group’s leader, Rahman Haj-Ahmadi, visited Washington last summer.

Biryar Gabar, one of 11 members of the group’s leadership, said there had been “normal dialogue” with American officials, declining specifics. One of his bodyguards said officials of the group met with Americans in Kirkuk last year.

Iranian officials have accused the United States of supplying the fighters and using them in a proxy war, though those assertions were denied by the American military. “The consensus is that U.S. forces are not working with or advising the P.J.A.K.,” said an American military spokesman in Baghdad, Cmdr. Scott Rye of the Navy.

A senior American diplomat said that there had not been any official contacts with the group and that he was unaware of its having received any support from the United States. He also said that Mr. Haj-Ahmadi, while in Washington, did not meet with administration officials.

Because the P.K.K. is on the State Department’s list of terrorist organizations and aiding such groups is illegal, the United States is eager to avoid any hint of cooperation with the P.J.A.K.

Guerrilla leaders said the Americans classify the P.K.K. as a terrorist group because it is fighting Turkey, an important American ally, while the P.J.A.K. is not labeled as such because it is fighting Iran.

In fact, the two groups appear to a large extent to be one and the same, and share the same goal: fighting campaigns to win new autonomy and rights for Kurds in Iran and Turkey. They share leadership, logistics and allegiance to Abdullah Ocalan, the P.K.K. leader imprisoned in Turkey.

While most Kurds are Sunni Muslims, the guerrillas reject Islamic fundamentalism. Instead, they trace their roots to a Marxist past. They still espouse what they call “scientific socialism” and promote women’s rights.

After skirmishes between the guerrillas and Iranian forces intensified this year, the Iranian military began shelling border villages in August, sending residents fleeing and killing livestock. The shelling drew angry criticism from Iraqi leaders, who condemned it as a disproportionate response.

But interviews with guerrillas suggest that they have inflicted considerable damage on Iran. While it is impossible to verify the claims, the leader of the P.K.K., Murat Karayilan, said the P.J.A.K. fighters had killed at least 150 Iranian soldiers and officials in Iran since August. And Biryar Gabar says 108 Iranians were killed in August alone.

The group said the intensity of its military actions varied with the degree of persecution of Kurds within Iran.

The P.J.A.K. guerrillas anchor their operations in small bases in the valleys equipped with generators, satellite television, spring wells and gardens of eggplant, pomegranates, tomatoes and peaches.

They have built several cemeteries to rebury the remains of fighters killed in previous years and to prepare for those yet to die. Pictures of more than 100 dead fighters, including women, cover the interior walls of a building inside one cemetery.

Up in the mountains, where they will stay for a year or more at a time, the fighters live spartan lives, subsisting on plain soups, tea, rice, beans, water and bread baked in makeshift ovens. They have a few tents and sleeping rolls, explaining that the only home they have is what they carry on their backs. The camps are designed for quick getaways.

The guerrillas are adept at hit-and-run tactics, and they thrive in the thin air almost two miles above sea level, climbing and hiking rapidly over the most challenging terrain. They send small teams into Iran armed with Kalashnikov rifles, rocket-propelled grenades, Russian-made sniper rifles and machine guns.

Typically, they will attack a few soldiers at the fringe of a larger group, said Sadun Edesa, a 22-year-old Iranian Kurd who said he had been fighting up here for five years. He said the small attack was usually all it took to derail an Iranian operation aimed at rooting out guerrillas inside Iran.

He was recently part of a four-man ambush team that sneaked into Iran and killed five Iranian soldiers, he said, before scampering back to camouflaged positions. “When you hit one of their groups like that, their military operation dies,” he said.

At one outpost, the guerrillas allowed a brief interview with the Iranian soldier they say was captured in the ambush described by the P.J.A.K. ambush commander, Bayram Gabar. The prisoner identified himself as Akbar Talibi, a member of the Islamic Revolutionary Guard Corps in Iran.

His uniform bore Guard insignia, and he sat cross-legged on a thin carpet as six guerrillas stood or squatted nearby, one resting a Kalashnikov rifle on his thighs. The prisoner said that of his 70-man unit, 15 had been killed and 17 wounded since August.

The Iranian military, the prisoner added, “wants to destroy P.J.A.K.” Iranian officials in Tehran did not respond to requests for comment about the guerrillas or the man the guerrillas identified as a captured soldier.

A former member of the Iranian Parliament, Jalal Jalilizadeh, who is Kurdish, said the guerrilla group increased its attacks and began singling out Revolutionary Guard members and assassinating other officials on the Iranian side of the border a year ago.

There are no official tallies of Iranian casualties, though Mr. Jalilizadeh estimated the total at around 100 since last year. He also confirmed several recent attacks described by the guerrillas, including the downing of an Iranian helicopter near the border in September, which killed at least six.

Mr. Shevger said he led the team that destroyed the helicopter, bringing it down it with a fusillade from machine guns and sniper rifles. “We found a weak point in the helicopter, and we opened fire,” he said. The fighting with Iran, he added, “will be worse a year from now.”

The group now has “far more” than 2,000 guerrillas fighting Iran, said Biryar Gabar, who added that most of them were based in Iran. There was no way to verify his claim.

But the group still has more than enough fighters in this part of Iraq to be a law unto itself, controlling the few roads in the area with checkpoints. A guerrilla outpost on the crest of a ridge of mountains straddling the border suggests that it holds sway over much of the border, while Iranian soldiers are garrisoned several miles away.

When the heavy shelling began in August, the Iranians also unleashed infantry attacks on guerrilla positions near this outpost but were beaten back, the guerrillas say. The outpost is concealed within a rock outcropping the size of a battle cruiser.

Above it, along the ridge, guerrilla sentries peer through binoculars at troop movements several miles inside Iran, careful to keep their heads down, they say, because the Iranians direct artillery fire at any sign of the guerrillas.

Nothing in their demeanor suggests that the guerrillas will soon abandon their fight. But their growing attacks inside Iran this year have put pressure on the Patriotic Union of Kurdistan, the dominant political party in the eastern sector of the Kurdistan region of Iraq, which sees Iran as a crucial trading partner. For their part, the guerrillas believe that the party, whose leader is the Iraqi president, Jalal Talabani, has become a toady for Iran.

But party officials say it would be foolish and shortsighted not to cultivate better relations with Iran and Turkey, from whom the landlocked Kurds obtain gasoline and other critical supplies. Kurdish leaders are also keenly aware that the guerrillas remain popular with the Kurdish public.

Tension between the party and the guerrillas apparently led to a skirmish in late August, when fighters crossed the border from Iran and were attacked by the pesh merga, the armed force affiliated with the party. Mr. Karayilan said he immediately phoned a counterpart at the P.U.K., who he said told him that the party was “getting pressure from Iran.”

Mr. Talabani has warned the guerrillas to put their weapons down or leave the border. But a senior party official close to Mr. Talabani admitted that “the people would be against us” if it took action against them.

The official, who was not authorized to speak publicly, declined to comment on the August skirmish, but he acknowledged that the pesh merga could not defeat the tough and proficient guerrillas. “If Iran and Turkey with their huge armies cannot control their borders,” he said, “how could we do that?”

The guerrillas also appear confident, though they fear the Iranian artillery. Mr. Edesa, the 22-year-old fighter, spoke with assurance about their capabilities against the Iranians. “They have a level of discipline in them as well,” he said. “But we are more disciplined. They are a military force, and they live in barracks. But we are a guerrilla force.”

Warzer Jaff contributed reporting from Iraqi Kurdistan, and Nazila Fathi from Tehran.