NATO leaders have heard a plea for more troops to be sent to Afghanistan.

Afghan president Hamid Karzai addressed the Istanbul summit on Tuesday and welcomed the commitment to increase the alliance's presence in the country from September.

But leaders including prime minister Tony Blair and US president George W Bush were told that more forces are needed and sooner.

Blair also met Karzai in Turkey, with the two men welcoming a move to boost NATO's role in supporting Afghanistan's autumn elections.

Troop levels will be increased by 3,500 to 10,000 in three months time.

Blair said: "This has been an important summit for NATO because we have stepped up to the mark.

"The key is that the response force NATO has is deployed to help the elections."

He added that there was "a real possibility" that the reinforcements would be deployed in time

Karzai stressed that more than five million Afghans had registered to vote and millions more refugees were returning home.

Blair said that showed "people in Afghanistan want this new future of democracy".

"Of course there are challenges. On the other hand, the progress Afghanistan is making is remarkable. We want to do what we can to help."

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While welcoming the announcement in a keynote address to the summit, Karzai said more support would still be appreciated.

"I would like you to please hurry... come sooner than September," he pleaded.

"I welcome very much your decision yesterday to send us security forces to help us with the elections.

"But... we need security forces today in Afghanistan to provide a secure environment for elections for the Afghan people and beyond."

The extra peace-keeping forces will be centred in the capital, Kabul, and the more stable north of the country.

It was thought that Karzai's administration had wanted NATO to enter the southern and eastern areas which remain more volatile.

'Happy'

However a 20,000-strong US-led combat force is expected to police these parts of the country in a bid to root out remaining al Qaeda and Taliban elements.

Karzai insisted that NATO was making a difference in Afghanistan and said he was "happy" with the arrangements.

"Kabul has about 5,000 troops and Kabul has been a very safe place for Afghanistan and for the international community," he said.

"If the strength goes to 10,000 troops and if that's deployed around the country, where we don't have NATO forces right now, that will bring about a lot of difference to the security of life, to the citizens of Afghanistan where they're deployed."

But he added: "The Afghan people keep coming to me from all parts of the country and are asking for increased participation of the international assistance security forces... They trust these forces."