Afghan President Hamid Karzai is due at the talks in Turkey's largest city Istanbul where leaders have pledged to take command of five military-civilian reconstruction teams in the north and send more troops to help ensure security during September's planned ballot.

"NATO is meeting its commitments to provide increased security to support the Afghan government, to support the upcoming electons," a senior NATO official said.

He added that the NATO secretary general Jaap de Hoop Scheffer "will deliver that message personally to President Karzai tomorrow morning."

Shortly after Iraq's interim government unexpectedly took over power from the US-led occupation coalition in Baghdad Monday, two days earlier than planned, NATO leaders also pledged to help train Iraq's new army.

After deep divisions over last year's invasion of Iraq plunged the military alliance into the worst crisis of its 55-year history, NATO members were keen to stress their unity in support for the Iraqi people.

Tensions rose outside the highly-guarded NATO conference centre too where left-wing protestors clashed with police who used water cannon, tear gas and plastic bullets to disperse them.

But the focus was set Tuesday to return to Afghanistan which has already welcomed NATO's 'major expansion' of the International Security Assistance Force (ISAF) by September polls.

"On the one hand any additional deployment at this stage, given the security situation and the upcoming elections, is good news," Foreign Ministry spokesman Omar Samad told AFP.

"But on the other hand, it obviously needs to be in adequate numbers to ensure a relatively free and fair election."

Karzai, as well as the United Nations and other agencies have repeatedly called on the alliance to expand its force from the current level of 6,500 ahead of the presidential and legislative polls.

A series of violent attacks in recent days targeting electoral workers and people registered to vote have come as Afghanistan is set to announce the exact date of the historic elections within days.

NATO took over ISAF last August in its first-ever mission outside Europe, complementing US-led forces there since the 2001 fall of the Taliban, but it has struggled to expand the force beyond the capital, Kabul, because of a shortfall in resources.

ISAF will now take command of additional military-civilian teams known as Provincial Reconstruction Teams (PRTs) in four northern areas of the country where it already runs one PRT in the city of Kunduz.

PRTs are small units of troops and civilian experts whose job is to improve security, foster reconstruction work and boost the influence of the central Kabul government in the provinces.

A senior official said here that the number of international peacekeepers would be boosted to potentially 10,000 during the elections, but that not all of these soldiers would be based in Afghanistan.

Details still need to be fleshed out but sources close to NATO chief Jaap de Hoop Scheffer said the expansion would break down into 500 troops for the PRTs and the deployment of a batallion of about 1,000 troops to help ensure the ballot is secure.

That would bring the forces' strength to about 8,000 troops, sources said.

Two other batallions are also due to be on standy outside Afghanistan.

NATO leaders also turn their thoughts to cooperation with non-member Ukraine on Tuesday on issues such as fighting terrorism, defence reform and civil emergency planning.

President Leonid Kuchma, who is also expected to attend, said earlier this month that the former Soviet republic was not yet ready to join NATO despite its wish to do so.

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