Nato defence ministers have agreed to establish a new Spearhead Force during a meeting at Nato headquarters in Brussels, Belgium.
During the Nato summit in Wales in September 2014, the member states agreed to create a force that can deploy at very short notice in response to crises in their territories.
Nato Secretary General Jens Stoltenberg said: "We decided that this very-high readiness force will consist of a land brigade of around 5,000 troops.
"These will be supported by air, sea and special forces.
"The lead element of this land brigade will be ready to move within as little as 48 hours, with the rest moving within a week."
In an event of a major crisis, the brigade would be supported by two more brigades as a rapid reinforcement capability, eventually increasing the number of the enhanced Nato Response Force to around 30,000 troops.
Spearhead will be led by France, Germany, Italy, Poland, Spain and the UK in rotations in the coming years to ensure that the unit can be sustained.
Stoltenberg added: "These countries will provide the main elements of the force and help bring together other allies, so this will be truly a multinational force.
"This is a strong signal of Nato solidarity and it shows that European allies are fully playing their part, taking the lead in protecting Europe.".
Nato already has a multinational Response Force in place that combines land, air, maritime and special operation forces, and can be deployed anywhere in the world for collective defence or crisis management within a maximum of 30 days.
In addition to finalising plans for Spearhead, ministers also agreed to immediately establish six command and control units in Bulgaria, Estonia, Latvia, Lithuania, Poland and Romania.
"If a crisis arises, they will ensure that national and Nato forces from across the Alliance are able to act as one from the start," Stoltenberg said.
"They will make rapid deployment easier, support planning for collective defence and help coordinate training and exercises."
Image: Nato defence ministers finalised the details of the new Spearhead Force during a meeting in Brussels, Belgium. Photo: courtesy of Nato.