ANKARA, Turkey Attack helicopters buzzed over a hilly region in southeastern Turkey on Sunday looking for Kurdish rebels after troops reportedly killed 15 separatist guerrillas in a morning operation far from the increasingly tense border with Iraq.
The fighting occurred in the predominantly Kurdish province of Tunceli, as the government pressed on with its efforts against the Kurdistan Worker's Party, or PKK, whose fighters have killed at least 42 people in the past month in raids on Turkish territory.
Turkey has threatened to send troops into Iraq to hunt down the rebels and has demanded the extradition of PKK leaders. The United States, Iraq and other countries have been pressing for Turkey to refrain from cross-border operations.
The top American commander in Iraq, Gen. David Petraeus, said Sunday the U.S. military was playing a role in trying to defuse the tensions, but he declined to elaborate.
"I am actually not going to say anything about what we may be doing with our long-standing NATO allies Turkey, although we clearly are doing things with them," he said.
The comments seemed aimed at allaying Turkish frustration, piqued Friday when the American military commander in northern Iraq, Maj. Gen. Benjamin Mixon, said he planned to do "absolutely nothing" to counter Kurdish rebels operating from the region.
Mixon handed over regional command to Maj. Gen. Mark Hertling on Sunday as scheduled. After the ceremony, Hertling told reporters that it would be "inappropriate" for him to discuss possible military measures while "diplomatic efforts are ongoing."
"For the most part both the Iraqi and the Turkish government, as well as the U.S. government are dealing with the challenges," he said at a news conference after formally assuming command of northern Iraq at a ceremony at a U.S. base near Saddam Hussein's hometown of Tikrit, 80 miles north of Baghdad.
In Turkey, pressure has been building on Prime Minister Recep Tayyip Erdogan to take action, with tens of thousands of Turks staging anti-PKK protests in recent weeks.
Erdogan called for unity between Turks and his country's minority Kurds Sunday but reiterated his government's determination to fight Iraq-based separatist Kurdish rebels.
"As long as we are firmly bound together, the treacherous separatist terrorist attacks will never reach their goal," Erdogan said in a message ahead of today's celebrations to mark the 84th anniversary of the Turkish republic.
"I want to declare this one more time: The struggle we lead against the separatist terrorism that aims to destroy our unity and our constitutional order will continue with belief and determination," he said.
A 9-mile race across Istanbul's Bosporus bridge to the European side of the city turned into an anti-PKK protest Sunday, with thousands of runners waving Turkish flags and shouting slogans denouncing the rebels.
But riot police cracked down quickly on a pro-PKK rally in the poor Okmeydani neighborhood of Istanbul, shooting tear gas into the crowd and dispersing the 150 demonstrators. Some young men then threw rocks at police before running into side streets.
Before the fighting in Tunceli, the Turkish military blocked roads into the region with armored personnel carriers and soldiers. By afternoon, long lines of trucks were backed up waiting to get through.
Tunceli is some 340 miles northeast of the province of Sirnak and 400 miles northeast of the province of Hakkari, the places where most of the recent fighting with the rebels has taken place. Sirnak and Hakkari border Iraq.
Fifteen rebels were killed in the operation, according to the private Dogan news agency, which was at the scene.A regional official confirmed the Turkish military conducted an operation against rebels, but declined to provide further details.
Contributing: Kim Gamel from Camp Speicher, Iraq