"I offered during my visit here to see if there are more capabilities that we can share with Turkey in terms of taking on this threat," he said.

In 2007, Washington had decided to provide "significant intelligence, surveillance and reconnaissance capacities and other equipments" to Ankara to back up its efforts to eradicate the outlawed Kurdistan Workers' Party (PKK), he added after talks with Turkish leaders.

Gates said General Ray Odierno, the top US officer in Iraq, discussed an "action plan" on possible further assistance with Turkish officials when he visited Ankara earlier this week.

"I think what we are seeing is a further intensification of the cooperation in an effort to deal with this threat," he said.

Turkey has long complained over thousands of PKK rebels holed up in the Kurdish-run north of Iraq from where they launch attacks on Turkish targets across the border as part of their 25-year separatist campaign.

In 2008, Turkey, the United States and Iraq set up a three-way committee to enact measures against the PKK, which is listed as a terrorist group by Turkey, the United States and much of the international community.

And in August, the Turkish government announced a series of steps to expand Kurdish freedoms with the hope of ending the PKK insurgency.

Although the drive faltered amid ban on the country's main Kurdish party, street protests and PKK violence, Ankara has vowed to push ahead with the reforms.

Gates added that Washington was also urging the autonomous Kurdish administration in northern Iraq to do its share in curbing PKK rebels.

"I met with President (Massud) Barzani of the Kurdish regional Government in Washington last week and we talked about the importance of KRG putting pressure on PKK to abandon violence as a political tool," he added.

The PKK picked up arms against Ankara in 1984 for self-rule in Kurdish-majority southeast Turkey, sparking a conflict that has claimed some 45,000 lives.