Turkish Prime Minister Recep Tayyip Erdogan said that he had invited his Iraqi counterpart Nuri al-Maliki to visit Ankara after the elections to discuss the presence of Kurdistan Workers' Party (PKK) rebels in northern Iraq.

Accusing Washingon of failing to fulfill its pledges of curbing the PKK, Erdogan said he would seek trilateral talks in order to resolve the dispute.

"We will ask them to take whatever step is necessary or we will do whatever is necessary," Erdogan was quoted by the Anatolia news agency as telling the Kanal-7 network.

Turkish Foreign Minister Abdullah Gul also said that Ankara would not refrain from action to eliminate the threat posed by the PKK, listed as a terrorist organisation by both Ankara and Washington.

"Our aim is not to enter Iraq, but to neutralize the terrorist organization. We will use our right (of self-defence) as long as the terrorist organization continues to harm Turkey," Gul told the TGRT television channel, Anatolia said.

Mounting PKK violence has been one of the dominant issues in campaigning ahead of the July 22 elections, with the opposition attacking Erdogan and his Justice and Development Party (AKP) for being soft on the issue.

The AKP is tipped to win the elections and secure a second term in power, with recent polls suggesting that the party will garner about 40 percent of the vote to get a solid parliamentary majority.

The PKK has been fighting for self-rule in Turkey's mainly Kurdish southeast since 1984 in a bloody conflict that has claimed more than 37,000 lives.

The rebels have stepped up attacks this year.

The army has launched a large-scale operation against the group in eastern and southeastern Turkey and massed troops on the border with Iraq, fuelling talk of a cross-border incursion to strike at rebels camps there.

Washington opposes any such action, fearing this could destabilise the relatively peaceful region and further strain already tense ties between Ankara and the Iraqi Kurds, staunch allies of the United States.