Reacting to the Russian aggression in Ukraine, the U.K. and six other NATO states are planning to form a joint expeditionary force that would bolster the alliance's power, the Financial Times reported Friday.

According to the report, the 10,000-strong force will incorporate air, naval and ground units. It is to be ready to respond to crises rapidly and to hold regular, frequent exercises in Europe and elsewhere.

The force will reportedly be led by British commanders. The other participating nations – Denmark, Latvia, Estonia, Lithuania, Norway and the Netherlands – will contribute special troops and units. Canada has also showed interest in joining the endeavor.

The details of the planned measure are yet to be worked out. Nevertheless, the Financial Times cited analysts as saying that the step could send a message to Russia, which, according to NATO, has deployed artillery and more than 1,000 troops in Ukraine.

Moscow still publicly denies its forces are fighting to support pro-Russian rebels who have declared independence in two provinces of eastern Ukraine. But the rebels themselves have all but confirmed it, saying thousands of Russian troops have fought on their behalf while "on leave."

Ukraine called on Friday for full membership in NATO, its strongest plea yet for Western military help.

Full Ukrainian membership of NATO, complete with the protection of a mutual defense pact with the United States, is still an unlikely prospect. But by announcing it is now seeking to join the alliance, Kiev has put more pressure on the West to find ways to protect it.

NATO Secretary General Anders Fogh Rasmussen said he respected Ukraine's right to seek alliances.

"Despite Moscow's hollow denials, it is now clear that Russian troops and equipment have illegally crossed the border into eastern and southeastern Ukraine," Rasmussen said. "This is not an isolated action, but part of a dangerous pattern over many months to destabilize Ukraine as a sovereign nation."