The huge Parliament Palace in Bucharest is hosting the summit
France has offered to send a battalion of troops to eastern Afghanistan, a Nato spokesman at the alliance's summit in Bucharest has confirmed.
The US says the French move will free up some of its troops to move to southern Afghanistan, where Canada had demanded Nato reinforcements be sent.
The spokesman also said there was agreement at the summit that Albania and Croatia be invited to join Nato.
But he said he did not expect speedy moves to admit Ukraine and Georgia.
French President Nicolas Sarkozy last week told the British parliament that France would send extra troops to Afghanistan.
However, Wednesday's statement at the Bucharest conference is the first confirmation that the move frees up enough US troops in the south to keep the Canadian deployment onboard.
Canada's parliament voted last month to extend its military mission in volatile southern Afghanistan to 2011 - but only if its allies sent reinforcements.
Earlier, US President George W Bush said he supported the admission of Albania, Croatia and Macedonia.
He also called for Membership Action Plans (MAP) to be extended to the former Soviet republics of Ukraine and Georgia, despite vehement Russian opposition.
On the first evening of the summit, Nato spokesman James Appathurai said there was a consensus that Albania and Croatia should be invited to begin accession talks.
"There is also a unanimous view within the alliance that the third country, the Former Yugoslav Republic of Macedonia, should as soon as possible be offered the opportunity to begin accession talks," he said.
However, agreement to admit Macedonia is being delayed by Greece's objections to the country's name.
Macedonia is also the name of a province in northern Greece, and Athens fears that this could imply a claim on its territory.
On Ukraine and Georgia, Mr Appathurai said: "I would be happy to be proved wrong but I do not expect MAP for Georgia and Ukraine."
Mr Bush said on Wednesday that Georgia and Ukraine should be offered "a clear path" towards the goal of Nato membership.
But Germany's Chancellor Angela Merkel said on arriving for the summit: "We have reached the conclusion that it is too early to give both countries MAP status."
French prime minister Francois Fillon said of Ukrainian and Georgian membership: "We think that it is not the correct response to the balance of power in Europe."