NATO put pressure on its member states on Thursday to send more troops to Afghanistan to help fight a Taliban offensive expected this spring against alliance forces.

NATO defence officials, including new U.S. Defence Secretary Robert Gates, gathered in Seville, Spain, on Thursday for a two-day meeting to discuss security in Afghanistan.

"I was very clear in saying that nations should fulfill all the commitments they have made and I hope they will will do so quickly," Gates told a news conference.

"We have an opportunity this spring to significantly disrupt the increasing level [of violence] we have seen in recent years caused by the Taliban. I'm optimistic this spring offensive will be ours."

U.S. Gen. John Craddock, NATO's new top commander, outlined plans at the meeting that called for an additional 2,500 troops to help the International Security Assistance Force. The NATO-led ISAF has about 35,000 troops in Afghanistan.

Some 37 countries, including Canada, have contributed troops to ISAF. But senior NATO officials have said for months that the force, trying to bring peace and security to Afghanistan, needs more troops.

According to U.S. officials, combat is expected in Afghanistan's southern and eastern regions along the border with Pakistan this spring and more mobile units could be deployed in areas where the fighting could be most intense.

The extra combat troops needed are in addition to the numbers recently announced by the U.S. and Britain, which supply more than half of the troops to ISAF.

Some European countries, including France, Spain, Italy and Turkey, have ruled out sending more combat troops to Afghanistan or lowering restrictions on their troops that prevent them fighting in the south and east, Reuters reported.

"More countries should take responsibility," Danish Defence Minister Soeren Gade said. "If we do not send more soldiers to Afghanistan, there is a risk that we may fail."

Spain has 550 troops in the west but said it will not contribute more. Germany has said it will provide six reconnaissance jets, but has no plans to increase its contingent of 3,000 troops in the north.

Meanwhile, Italy has 1,950 personnel in the country but must obtain financial support from its parliament to maintain its troop numbers.

Must do part: secretary general

NATO Secretary General Jaap de Hoop Scheffer said before the meeting that all member states must do their part.

"It is important that all nations participate because of course there is an element of solidarity in NATO," he said.

A U.S. official travelling with Gates to the meeting told AP on condition of anonymity that NATO must strike first against the Taliban this spring.

"We think the upcoming spring in Afghanistan is a pivotal moment in the conflict, and we're encouraging the allies to do as much as they can, as soon as they can," said the official.

"The offensive should be our offensive. That's the offensive we've been communicating to the allies," he said.

The U.S. announced in January that it will lengthen the tour of more than 3,000 of its soldiers, while Britain said it will send 800 extra combat troops to southern Afghanistan in the next few months.

Security was tight in Seville on Thursday while the ministers met.

About 4,600 police officers were stationed around the city while NATO planes, Eurofighter jets and F-18 aircraft were in charge of the airspace.

Canada has more than 2,000 troops in Afghanistan, with the majority stationed in the volatile province of Kandahar.

Forty-four Canadian soldiers have been killed in Afghanistan since Canada first sent troops to the country in early 2002.

With files from the Associated Press