US Secretary of State Condoleezza Rice promised Friday that the United States will redouble its efforts in helping Turkey fight Kurdish rebels in northern Iraq, according to dpa. "No one should doubt the commitment of the United States to this issue," Rice told a joint press conference with her Turkish counterpart Ali Babacan in Ankara. "The United States considers the PKK (Kurdish Workers' Party) as a terrorist organization, and indeed we have a common enemy. Rice said that in her meetings in Ankara, discussions were held on a comprehensive plan on how to deal with PKK rebels based in northern Iraq, the details of which will be further discussed during a meeting of Turkish Prime Minister Recep Tayyip Erdogan and US President George Bush in Washington on Monday. Turkey has massed troops on its border with Iraq and has threatened to launch a large-scale cross-border operation if its demands of action against the PKK are not met. The Turkish government has come under increasing public pressure to launch such an operation after a month of fierce fighting in which PKK guerrillas have launched attacks inside Turkey after having crossed the border from Iraq. The last month has left almost 100 dead. Eight soldiers have also been kidnapped by PKK rebels. The Turkish military estimates there are around 3,500 PKK rebels holed up in mountainous northern Iraq. Washington fears that a Turkish incursion may result in civilian casualties and is concerned it may lead to a breakdown in order in northern Iraq, the only relatively calm region of the country. Rice did not specifically speak out against such an operation on Friday but said that the fight against the PKK would take "commitment and persistence". "This is a very difficult problem. Rooting out terrorism is hard... But with commitment and persistence I am certain we will be able to make progress," Rice said. Babacan made it clear that Turkey expects the United States to make concrete steps in the near future. "The time for words is over, it is time for action," Babacan said. Rice also met Erdogan and Turkish president Abdullah Gul in Ankara on Friday and was scheduled to fly to Istanbul Friday evening to take part in an Iraqi neighbours regional conference. In Istanbul, the speaker of the northern Iraq Kurdistan Regional Parliament, Adnan al-Mufti, appealed to Turkey to give diplomacy another chance. "The door is still open," Al-Mufti said and called on the PKK to lay down its arms. "Force is a language that is no longer modern." The regional conference officially begins on Saturday with the participation of 16 foreign ministers, representatives of the G-8 and UN Secretary-general Ban Ki-Moon. The main aim is to discuss ways in which to stop ongoing violence in Iraq but participants fear that Turkey-PKK crisis could overshadow the meeting.