Nato is to expand its peacekeeping mission in Afghanistan with more forces being sent to western regions.
Isaf troops have been mainly confined to Kabul and the north
Nato Secretary General Jaap de Hoop Scheffer announced the move after Nato defence ministers agreed to further deployment at a meeting in Nice.
The new troops, for Herat and three other western cities, will help Nato meet its plans to operate in the whole of the country by 2006.
Nato has a force of about 8,500 troops deployed in Afghanistan.
After the meeting, Mr De Hoop Scheffer said: "We have the resources. We need to expand."
Spain, Italy and Lithuania agreed to send more troops after months of delays.
US Defence Secretary Donald Rumsfeld praised the move, saying it would have been inconceivable for Nato to run missions in Afghanistan in the past.
"There are a lot of good things happening in this alliance," he told reporters after the Nice meeting.
Nato's current International Security Assistance Force (Isaf) comes from more than 30 countries but has been deployed in Kabul and northern regions.
The US leads some 18,000 troops in Afghanistan
The United States has long called for expanded Nato deployment to dovetail with the US-led force of around 18,000.
US-led troops continue to hunt al-Qaeda and Taleban militants, along with al-Qaeda leader Osama Bin Laden, in the Afghan-Pakistan border areas.
Nato's ministers have agreed in principle to merge their own peacekeeping force with the US operation, called Enduring Freedom.
The BBC's defence and security correspondent, Paul Welsh, says the new Nato troops will be in the hundreds, not thousands, but that they will allow four new reconstruction teams for the west.
He says some Nato members may have been annoyed by US appeals for more troops for Iraq. Sending troops to Afghanistan is less politically charged.