KIEV, March 2 (Reuters) - Ukraine has called up all military reserves and ordered its armed forces to be combat-ready as soon as possible, the country's top security official said on Sunday.

Andriy Paruby, Secretary of the Security Council which groups top security and defence chiefs, said an order had also been given to the Foreign Ministry to seek U.S. and British help in guaranteeing the security of Ukraine.

The decisions followed a vote by Russia's upper house of parliament on Saturday which authorised President Vladimir Putin to deploy troops in Ukraine.

Reading out the order after a meeting of the council, Paruby said the Defence Ministry was to "organise and conduct training with the necessary amount of people of military age."

Ukrainians up to the age of 40 are considered of military-age. In the southern region of Crimea, which has an ethnic Russian majority and is home to a Russian naval base, armed groups have taken control of key buildings and installations.

The armed forces, he said, would step up security at energy facilities.