(Adds details, background) ISTANBUL, Nov 3 (Reuters) - Iraqi Prime Minister Nuri al-Maliki promised on Saturday to take urgent measures against Kurdish rebels based in northern Iraq, including shutting down their offices. Ankara says numerous pledges by U.S. and Iraqi authorities have failed to materialise and it has warned that unless immediate action is taken Turkey will launch a military cross-border incursion to crack down on PKK guerrillas using northern Iraq as a base to carry out deadly attacks in Turkey. "We are taking serious measures," Maliki said in a speech at a one-day regional conference on Iraqi security held in Istanbul. Turkey, a NATO member with the alliance's second-biggest army, has sent up to 100,000 troops to the Iraqi border, backed by tanks, artillery and aircraft. But Baghdad and Washington have urged Ankara to refrain from a major operation in an area that has so far been spared the worst of the violence in Iraq. Turkey wants PKK camps shut and their leaders arrested in northern Iraq. Maliki, who has in the past promised to shut PKK offices, also urged Iraq's neighbours to do more to prevent "terrorists" from crossing over into Iraq and to do a better job of protecting border areas.
