Britain, Germany and the United States advanced plans on Tuesday to spearhead a new NATO force on Russia's border from next year, and Russian President Vladimir Putin ordered snap checks on combat readiness across his armed forces. Weeks before a critical NATO summit in Warsaw, three of NATO's biggest military powers said they would each command a battalion across the eastern flank to help deter any show of force such as that deployed by Moscow in Crimea in 2014. In a reminder of Russia's efforts to bolster its military readiness, its armed forces started carrying out spot checks on its units, as well of weapon and equipment depots. Russian Defence Minister Sergei Shoigu said the goal of the June 14-22 drill was to ensure the ability of his military to "carry out planned activities, including mobilisation." NATO's battalions are part of a wider deterrent to be approved at the Warsaw summit on July 8. It will involve troops on rotation, warehoused equipment and a highly mobile force backed by NATO's 40,000-strong rapid reaction unit. NATO hopes the complex plan can discourage Russia from orchestrating the kind of campaign used to annex Ukraine's Crimea peninsula in February 2014 and which has left eastern allies nervous of their former Soviet overlord. Berlin and Washington also said that they would send troops to the new force, which is expected to total about 4,000 soldiers, with contributions from other allies. France is sending a company of about 250 troops to Britain's battalion. Germany is likely to deploy to Lithuania, the United States to Poland and Britain to Estonia, on a six- to nine-month rotating basis. Other NATO nations will eventually take command responsibilities, diplomats told Reuters.