Turkish warplanes and troops have attacked Kurdish rebels inside Iraq and forces were being built up on the border, but Ankara was holding back from any major strike for now, military sources said on Wednesday.

News of the sorties, between Sunday and Tuesday evening in which Turkish warplanes flew 20 km (13 miles) into Iraq and some 300 ground troops advanced about 10 km, put Baghdad under greater pressure to act against PKK rebels operating from the north of its territory.

The sources said 34 rebels of the outlawed PKK (Kurdistan Workers Party) had been killed in the sorties. All Turkish troops involved in the operations had returned to Turkey.

In the face of intense concern by Washington and Baghdad over a possible major incursion into northern Iraq by Turkish forces, Ankara says it is still hoping for a diplomatic solution to the crisis.

But, though Baghdad has pledged to act against the rebels, Prime Minister Tayyip Erdogan's government is under heavy public pressure to take tough action, especially after PKK rebels killed 12 soldiers near the border on Sunday.

In Ankara, Turkey's National Security Council comprising political leaders and army top brass was expected to mull possible economic measures against the Kurdish administration of northern Iraq over its continued failure to tackle the rebels.

"We are reinforcing our troops near the border at Silopi and Uludere with men drawn from other parts of the country," a military source told Reuters.

Turkey, which has NATO's second biggest army, has deployed as many as 100,000 troops, backed by tanks, F-16 fighter jets and helicopter gunships, along the mountainous border in preparation for a possible large-scale strike.

Military sources, speaking to Reuters, said the sorties carried out from Sunday to Tuesday evening were in line with similar operations in the past.

"Further 'hot pursuit' raids into northern Iraq can be expected, though none have taken place so far today (Wednesday)," a military official said.

IRAQI PLEDGES

Washington and Baghdad fear a major Turkish incursion into northern Iraq could destabilize the whole region.

On Tuesday, Iraq promised visiting Turkish Foreign Minister Ali Babacan it would close the offices of Kurdish rebels and work to prevent them launching attacks on Turkey.

But Baghdad gave few details of how it could stop the rebels mounting cross-border raids from their remote mountain hideaways in northern Iraq, where the central government has little clout. And the publication of photographs said to show eight Turkish soldiers captured by the PKK added to pressure on Ankara to act.

"We need to go beyond words," Babacan told reporters at Ankara airport on his return late on Tuesday.

"We emphasized in Baghdad that this is not a fight with mosquitoes, it is a matter of draining the swamp."

Ankara blames the PKK for the deaths of more than 30,000 people since the group launched its armed campaign for an ethnic homeland in southeast Turkey in 1984.

Turkey's National Security Council, under the chairmanship of President Abdullah Gul, was due to discuss the latest developments at a meeting starting at 2 pm (1100 GMT).

"The prime minister has indicated this meeting could produce economic sanctions, for example, cutting off electricity to northern Iraq or the closure or slowing down of traffic at the Habur border gate," said Suat Kiniklioglu, an AK Party lawmaker.

"We have gained a bit more time to think about what actions to take and consider the implications of any action. There is a growing understanding in the United States and Europe of Turkey's legitimate right to deal with the PKK in Iraq."

Northern Iraq depends heavily on Turkey for power, water and many food supplies. Iraqi Kurdish leader Masoud Barzani has infuriated Turkey by refusing to act against the PKK. He has said his peshmerga fighters would resist any Turkish incursion.

(Additional reporting by Gareth Jones and Selcuk Gokoluk in Ankara and Ferit Demir in Tunceli)