The attack, blamed on the banned Kurdistan Workers Party (PKK), came amid speculation Turkey may send troops into neighboring northern Iraq to crush Kurdish rebels based there, despite pleas from the United States to avoid military action.
Three people thought to belong to the PKK drove into the gendarmerie complex in the eastern province of Tunceli, opened fire and threw a grenade, killing eight and wounding six more. One guerrilla was also killed, the security sources said.
The gendarmerie is a paramilitary force responsible for security in rural areas of Turkey.
The attack, which security sources had earlier described as a suicide bombing, is the second big assault on Turkish forces in two weeks and will exacerbate political and security tensions in Turkey, which is preparing for elections in July.
In a move one newspaper said may be an attempt to prepare the diplomatic ground for a possible army incursion into Iraq, a Foreign Ministry official said Turkey would submit a report to the United Nations this week spelling out its concerns about the PKK in Iraq and arguing a legal right to act against them.
Turkey's permanent U.N. representative, Baki Ilkin, will also hold talks with U.N. Secretary-General Ban Ki-moon this week, the official said.
"First diplomacy," said Monday's headline in the Sabah newspaper, suggesting military action may not be far off
Turkey's powerful army General Staff says an operation in Iraq is necessary, and Prime Minister Tayyip Erdogan said last month he saw eye-to-eye with the military over possible action.
EU SEEKS INFORMATION
Ankara has long urged U.S. and Iraqi government forces to crack down on an estimated 4,000 PKK guerrillas based in Iraq.
But U.S. troops, battling an Arab insurgency in central and southern Iraq, are reluctant to intervene in the relatively peaceful, mainly Kurdish north of the country and have also asked Ankara to avoid military action.
Turkey insists it has the right under international law to send troops into Iraq in self-defence if need be. It has long maintained a small low-profile contingent on the Iraqi side of the border, involved largely in reconnaissance, and complained last week that a unit had been harassed by local armed forces.
Parliament must approve any extended major operation and the government has said no plans are currently under consideration.
Senior officials of the European Union, which Turkey aims to join, said they had sought information about Turkish plans from Foreign Minister Abdullah Gul in talks in Ankara on Monday but said there was no suggestion an incursion was being planned.
"Mr Gul told us the Turkish government naturally wants to protect its own people and that there is therefore a need to take action against terrorist activity," German Foreign Minister Frank-Walter Steinmeier told a joint news conference with Gul.
"I received no indication an action is planned with a view to a military intervention in northern Iraq," he said.
The Iraq situation has fuelled a strong rise in nationalism and anti-American sentiment in Turkey ahead of July's elections.
The Kurdish separatist campaign, in which some 30,000 people have been killed since 1984, is a major issue for many.