Afghanistan and Pakistan held their first talks on Tuesday since the assassination of an Afghan peace negotiator, in a meeting hosted by Turkey to heal a rift undermining prospects of ending the Afghan war.

Hamid Karzai and Asif Ali Zardari met along with Turkish President Abdullah Gul while their army chiefs consulted ahead of an international conference on Afghanistan.

Afghanistan accuses Pakistan's Inter-Service Intelligence (ISI) agency of supporting Taliban insurgents who have launched a string of dramatic attacks in recent months as foreign troops prepare to pull out most combat troops by 2014.

It broke off talks with Pakistan after the assassination in September of Afghan peace negotiator Burhanuddin Rabbani, which it blamed on Taliban insurgents it said were based in the Pakistani city of Quetta.

Now is perhaps the time to try to reverse the course, a Turkish official said on the eve of the talks between Karzai, Zardari and Gul.

We sense that they have a genuine wish to talk to each other because they realise this trend is not helping either of them, he said.

Islamabad, which denies supporting the Taliban, has complained in turn that insurgents from the Tehrik-e-Taliban Pakistan (TTP), or Pakistani Taliban, have been using Afghanistan as a base from which to launch attacks in Pakistan.

With the United States and its allies hoping to hand over responsibility for security to Afghan forces by 2014, the rift between Islamabad and Kabul has stoked fears Afghanistan will face an escalating civil war as foreign troops pull out.

The assassination of peace negotiator Rabbani reduced hopes that talks with the Taliban might offer a way forward, though the United States has said it remains open to reaching an accord with insurgents ready to sever ties with al Qaeda, renounce violence and respect the Afghan constitution.

Karzai, underlining Afghan suspicions that Islamabad is backing the insurgents, said that any negotiations should be held directly with Pakistan instead.

PAKISTAN ARMY CHIEF AT TALKS

With Pakistan's foreign and security policy set largely by the Pakistan Army, its chief, General Ashfaq Pervez Kayani, was holding separate talks in Istanbul with Afghanistan army chief General Sher Mohammad Karimi and the head of the Turkish military.

The trilateral talks will be followed by a regional conference on Afghanistan to be attended by Indian Foreign Minister S.M. Krishna and their counterparts from France and Germany, among others.

U.S. Secretary of State Hillary Clinton cancelled her trip because of the ill health of her mother.

The United States has been pushing Pakistan to take action against militants it says enjoy safe haven both in Quetta and its tribal areas bordering Afghanistan.

Most recently its focus has been on the Haqqani network, which says it owes allegiance to the so-called Quetta shura Taliban, but has traditionally been seen close to the ISI.

Pakistan denies supporting the Haqqani network and attributes its lack of action against the group to the fact that its army is already overstretched fighting Pakistani Taliban militants and others.

A senior U.S. administration official said on Monday that Pakistani action against the Haqqani network did not necessarily need to be military.

Instead it would include ensuring that intelligence doesn't go to the Haqqani network and that they don't benefit from financial resources or flow of finances.