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 UN this week spelling out its concerns about the PKK in Iraq and arguing a legal right to act against them.
Baki Ilkin, Turkey's permanent UN representative, will also hold talks with Ban Ki-moon, UN secretary-general, this week, the official said.
"... the Turkish government naturally wants to protect its own people and that there is therefore a need to take action against terrorist activity"
Frank-Walter Steinmeier, German Foreign Minister
Monday's headline in the Sabah newspaper said "First diplomacy", suggesting military action may not be far off.
Turkey's powerful army general staff say that an operation in Iraq is necessary, and Tayyip Erdogan, the prime minister, said last month he saw eye to eye with the military over possible action.
Ankara has long urged US and Iraqi government forces to crack down on an estimated 4,000 PKK fighters based in Iraq.
But US troops, battling a predominantly-Arab uprising 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 seeks to join, said they had sought information about Turkish plans from Abdullah Gul, the foreign minister, in talks in Ankara on Monday, but said there was no suggestion an incursion was being planned.
At a joint news conference with Gul, Frank-Walter Steinmeier, the German foreign minister, said: "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.
"I received no indication an action is planned with a view to a military intervention in northern Iraq."
The Iraq situation has fuelled a strong rise in nationalism and anti-American sentiment in Turkey in the run-up to July's elections.
The Kurdish separatist campaign, in which some 30,000 people have been killed since 1984, is a major issue for many.