Turkey hosts the presidents of Afghanistan and Pakistan Tuesday for a trilateral summit designed to reduce tensions and promotecooperation between the two neighbours amid stepped-up Talibanattacks.

Turkish President Abdullah Gul will hold separate talks with Hamid Karzai of Afghanistan and Asif Zardari of Pakistan before the three-way talks later Tuesday, said a Turkish diplomatic source.

The meeting ahead of an international conference on Afghanistan on Wednesday in Turkey is the first between the two neighbours since the assasination of the former Afghan leader Burhanuddin Rabbani on September 20.

Kabul has accused Islamabad of refusing to cooperate in the investigation of the murder, which according to Afghan authorities, was planned in Pakistan and committed by a Pakistani suicide bomber.

"We will try to resolve their differences," said a Turkish diplomatic source speaking on condition of anonymity, adding that all countries in the region have a duty to work for peace in Afghanistan.

The meeting comes just days after 17 people died in the deadliest attack yet in Kabul against the US-led NATO mission, including 10 Americans, and three days after a US-run base in Kandahar was targeted.

The three presidents will also discuss their fight against the Islamist insurgency and sign agreements enshrining their commitment to cooperate in the field of security, according to the same source.

The meeting is the sixth in Turkey, a NATO member, since the consultations were established in 2007 to encourage both countries to cooperate against extremism.

The previous meetings between the two countries' presidents, military leaders and intelligence chiefs resulted in the parties' commitment to improve cooperation.

Later Tuesday, the three presidents will sign two agreements on security cooperation, including a military one, said the Turkish source, adding that the deals will forge cross-border cooperation against terrorism.

Kabul, like the United States, has said Islamabad is not doing enough against the Taliban and Al-Qaeda which have found refuge in the Pakistani tribal areas bordering Afghanistan and regularly carried out attacks against the Afghan, US and NATO forces in Afghanistan.

The trilateral summit will be followed by an international conference Wednesday in Istanbul. Twenty countries and organisations are expected to attend the Istanbul event.

US Secretary of State Hillary Clinton changed her plans and cancelled her visit to Istanbul at the last minute to stay with her ailing mother.