KABUL, April 1, 2008 (AFP) - President Hamid Karzai headed Tuesday to a NATO summit where he is to tell countries tackling a Taliban-led insurgency that Afghanistan lacks the capacity to effectively fight terrorism, his office said.

Karzai is due to address a special session Thursday of the April 2-4 summit at which countries in the NATO-led International Security Assistance Force (ISAF) are expected to pledge extra troops and resources to the battle.

A statement from Karzai's office announcing his departure said the president's speech would cover 'the lack of capacity to effectively fight terrorism.'

It would also touch on the need for the Afghan National Army to take greater responsibility for security in Kabul and other major cities, and the NATO strategy in Afghanistan, it said.

Karzai would meet the heads of several nations with troops taking part in ISAF, including the leaders of major players Britain and Canada, as well as UN Secretary General Ban Ki-moon, who has just sent a new envoy to Afghanistan.

Last year was the deadliest of an insurgency launched by the Taliban after the extremists were removed from government in late 2001 in a US-led invasion.

The violence is particularly intense in the south, where 17 of the 39 nations in ISAF are under pressure.

US Defence Secretary Robert Gates said Monday there was a 'good possibility' some allies would step forward to offer more troops for ISAF but he suggested it would fall short of the three manoeuvre brigades requested by commanders.

After the NATO summit, Karzai was to travel Friday to Hungary, which has about 200 troops in ISAF, to meet top officials there, his office said.

He was accompanied by his foreign minister, Rangeen Dadfar Spanta, and defence minister, Abdul Rahim Wardak, as well as other top officials.