Sunday, June 17, 2007 | By Joshua Partlow

IRBIL, Iraq - Iraqi border police believe neighboring Turkey has amassed 20,000 to 30,000 soldiers along its southern border with Iraq. Turkish helicopters have flown into Iraqi airspace to conduct missions against Kurdish rebels in the mountainous region, and Turkish mortar shells regularly crash down on Iraqi soil, according to U.S. and Iraqi officials

About two weeks ago, a team of Turkish special forces soldiers was discovered in the city of Sulaymaniyah, about 115 miles into Iraqi territory.

The view from northern Iraq of the growing Turkish military presence and escalating conflict with separatist rebels is of increasing concern to Iraqi border officials and their U.S. military counterparts who monitor the 200-mile border. Drawing another country into the maelstrom of Iraq would represent a serious blow to an already unstable political situation and put Americans in a precarious position between two supporters: the Turks, who are NATO allies, and the Kurds, who are close partners in Iraq.

But in interviews last week in the Kurdish semiautonomous region in Iraq, officials responsible for the border said they did not expect a major Turkish incursion and hoped the tensions would dissipate with diplomatic negotiations.

"I can't believe that the Turkish people would attack Kurdistan. I just can't believe that," said Brig. Gen. Muhsen Abdul Hasan Lazem, an Iraqi Interior Ministry official who leads the border force. "All this staging is a show of force, but I don't think they're going to do anything. They are passing a message to the Kurdistan government that they are serious."

It is a display that has grown more brazen in recent weeks. For decades, Turkey, which has a large Kurdish minority, has suffered attacks from the Kurdistan Workers' Party, or PKK, a militant group based in northern Iraq that wants an independent Kurdistan.

In response to recent attacks, including a bombing in Ankara in May that killed eight people, Turkey has expanded its force along the border, deploying additional artillery and dozens of tanks. A contingent of Turkish soldiers -- nearly the size of a brigade -- already operates inside Iraqi territory, a remnant of earlier invasions into Kurdish territory, according to U.S. and Iraqi officials. And some Turkish politicians have called for an invasion to confront the rebels.

But the prospect of a large-scale Turkish military movement into Iraq appeared to lessen last week when Turkish Prime Minister Recep Tayyip Erdogan said his country should focus on the large number of militants operating in Turkey before seeking them out in Iraq. And Iraqi officials acknowledge that Turkish shelling of the border regions and troop movements in the area have been a seasonal pastime for years as the snows melt and activity picks up across the border.

Still, some Kurdish leaders are angry at what they describe as escalated Turkish aggression that extends beyond an animosity toward rebel groups.

"Turkey has a problem with the existence of Kurds," Massoud Barzani, president of the Kurdish regional government in Iraq, said Wednesday, according to Kurdish television reports. "We have always advocated good neighborliness on the basis of mutual interests and nonintervention; nonetheless, we do not accept violations and threats."

The Iraqi government has walked a fine line on the Kurdish issue. The Foreign Ministry has formally demanded that Turkey halt its shelling inside Iraq but has also condemned attacks by Kurdish separatists. Iraq's foreign minister, Hoshyar Zebari, a Kurd, said at a meeting in New York on Thursday that the issue could be resolved only through dialogue.

"We've been very honest," Zebari said, according to the Reuters news agency. "We're fighting in the neighborhoods of Baghdad. We can't release Iraqi troops to the Kurdish mountains."

The U.S. military has a small contingent in Iraq's Kurdish north and a limited view of activity along the northern border. A team of about a dozen U.S. soldiers works with the Iraqi border force in the Kurdish capital of Irbil and visits the outposts along the border; a U.S. Special Forces team also works in the area. On one trip, Special Forces Col. Johnny C. Strain, who leads the border transition team, saw a 1.5-mile-long airstrip with 18 Turkish tanks guarding it.

The team's intelligence officer, Sgt. 1st Class Jody Reynolds, said Turkish forces have been "mortaring fairly regularly" along the border and "conducting cross-border operations, in order to push back PKK elements or to retaliate."

"There are Iraqi Kurds who have been abandoning their homes" along the border, Reynolds said. "And with good reason. Who wants to live where they're going to be shelled?"

Within the past two weeks, a team of Turkish special forces soldiers wearing civilian clothes was stopped by Kurdish militiamen, known as pesh merga, at a checkpoint in Sulaymaniyah and asked for identification, an episode that worsened tensions between the two countries, Strain said.

"It just added to the fuel of what was already going on," he said.

Iraqi officials estimate that about 3,000 PKK members are in northern Iraq. The group controls some routes into the country and taxes passing vehicles to help finance its operations, U.S. officials said. One senior Iraqi security official said the United States needs to "pinch Barzani" to make him take a harder line against the rebels. The Iraqi border force does not have the power to stop Turkish troops from coming into Iraq or to keep rebels from pushing out to Turkey, the security official acknowledged.

"They only can write reports," said the official, who spoke on condition of anonymity.

To the U.S. military, having to take sides in an open fight inside Iraq between Turkey and the Kurds is not a pleasing prospect. Brig. Gen. Dana J.H. Pittard, who works with Iraqi security forces, said that "there appears to be some activity on the Turkish side, but it may just be brinksmanship."

"We can't have it to where we have friction with a NATO ally," Pittard said. The Kurdish regional government "must help out in muzzling the PKK or suffer the consequences."

Staff researcher Robert E. Thomason in Washington contributed to this report.