Washington is supplying Turkey with intelligence on the hideouts of Kurdish separatists on the Iraqi border, a Pentagon spokesman has said.

Geoff Morrell, the Pentagon press secretary, said on Wednesday that the US is helping Ankara gain the "actionable" intelligence Washington says is needed before any military strike.

He said: "We are assisting the Turks in their efforts to combat the PKK by supplying them with lots of intelligence.

"The key for any sort of military response ... is having actionable intelligence."

The Turkish army told AFP agency it had killed 15 PKK fighters on Wednesday.

Morrell also said: "We are making efforts to help them get actionable intelligence.

"Actionable" intelligence refers to information that can be acted upon, such as information that pinpoints the location of a target for a military strike.

Turkey has threatened to send its forces across the border into northern Iraq against the Kurdish Workers' party (PKK) in response to stepped up attacks inside Turkey by the separatist group.

Morrell said the US has shared intelligence - a "lot of intelligence" - with Turkey for a long time, but has increased intelligence sharing recently.

Turkey, which has Nato's second biggest army, has deployed as many as 100,000 troops on its border with Iraq, and says it will launch a major cross-border incursion against the PKK unless US and Iraqi forces act.

For its part, Iraq announced on Wednesday that it was setting up further checkpoints to restrict the passage of Kurdish fighters and to cut supply lines.

Last week, Robert Gates, the US defense secretary, said Turkey and the US needed better intelligence about the location of PKK fighters in Iraq before launching a military strike. Gates would not discuss intelligence last week.

Morrell would not say how the US was gathering the intelligence.

A Turkish army statement said that the latest fighting was in the Cudi Mountains in Sirnak province where Cobra helicopters and artillery had been pounding PKK positions since Monday.

Three soldiers were killed in the clashes, the army said.

PHOTO CAPTION

A Turkish commando takes up position on a mountain in Sirnak