President Abdullah Gul chaired talks with top government and military officials after the separatist Kurdistan Workers' Party (PKK) killed 12 soldiers over the weekend, triggering nationwide outrage and piling pressure on Ankara for tougher measures.

The surging violence dealt a heavy blow to an already fragile government initiative to boost Kurdish freedoms and investment in the impoverished southeast in a bid to end the bloody 26-year insurgency in the region.

In a message of support, the United States said it was ready to "urgently" consider any new request for help from Ankara.

"The PKK is a common enemy of both Turkey and the US and we actively support the efforts of our Turkish allies to defeat this terrorist threat," US ambassador James Jeffrey said in a statement.

The PKK is listed as a terrorist group by Ankara and much of the international community, including Washington.

The army suffered most of its weekend casualties when dozens of rebels assaulted a border unit at the Iraqi frontier Saturday, prompting an air raid on PKK hideouts in northern Iraq. At least 12 rebels were also killed.

The PKK has long taken refuge in the rugged mountains of northern Iraq, and US intelligence on rebel movements has been vital for Turkish counter-strikes.

Jeffrey stressed "there has been no change in the level of US-Turkey intelligence sharing."

Turkey's "no" vote on fresh UN sanctions against Iran and a simmering crisis with Israel sparked concern here that the United States may respond by scaling down cooperation against the PKK.

Washington has said it was disppointed by Turkey's stance on Iran and expressed concern over Turkish-Israeli ties, which plunged into deep crisis last month after Israeli forces killed nine Turks on a Gaza-bound aid ship.

Army chief Ilker Basbug played down suggestions of an intelligence failure in the attack on the border guard.

"We have always been grateful for the intelligence the US has provided," Anatolia news agency quoted him as saying in Canakkale, northwest Turkey.

Over the past 10 days, Basbug said, the Turkish army has also started using its own Israeli-made drones to monitor the PKK.

The drones are being used by Turkish personnel "at a certain distance in the north of Iraq in coordination with the Americans," he said.

His remarks came in response to media speculation that the newly-bought drones were idle after Israeli operators left Turkey amid bilateral tensions.

Gul's office said additional measures were decided at the security summit, without giving details.

"The need to review intelligence and the organisation of personnel" in the southeast were also discussed, it said, emphasising "the importance of more efficient coordination... with surrounding and related countries."

The surging violence cast a shadow also on Turkish efforts to mend fences with the Iraqi Kurds, whom Ankara had often accused of tolerating the PKK in their autonomous region.

Their leader, Massud Barzani, had paid a landmark visit to Ankara this month pledging "all efforts" to curb the rebels.

Iraqi Kurdish officials said Sunday that Turkish troops crossed the border to pursue the rebels, advancing 10 kilometres (six miles) into Iraqi territory, an operation the Turkish army has not confirmed.

Iraqi Foreign Minister Hoshyar Zebari, himself a Kurd, slammed the "unilateral" action and urged Ankara to return to peaceful efforts to end the conflict.

Ankara's so-called "Kurdish opening" -- announced last year -- has already faltered amid an opposition outcry that the government is bowing to the PKK and persistent rebel attacks.

The PKK took up arms in 1984, sparking a conflict that has cost about 45,000 lives.