By Karen Freifeld and Daphne Psaledakis
(Reuters) -The United States on Friday increased pressure on Myanmar's military rulers in response to their February takeover, adding four companies it said support the military to its trade blacklist and imposing sanctions on key military officials.
The moves follow earlier measures by the United States, which along with other Western nations has led condemnation of the military since it took power alleging fraud in an election won by Aung San Suu Kyi's party in November.
"Today’s measures further demonstrate that we will continue to take additional action against, and impose costs on, the military and its leaders until they reverse course and provide for a return to democracy," U.S. Secretary of State Antony Blinken warned in a statement on Friday's action.
The U.S. Treasury Department said it had placed sanctions on seven key members of the military, which it accused of using lethal force against protesters.
Among those targeted are members of the State Administrative Council, the Minister for Information and other officials.
The Treasury also designated 15 family members of previously designated Myanmar military officials.
The new entities affected by trade restrictions are involved in copper mining and satellite services, according to a U.S. government posting.
They are Wanbao Mining Ltd. and its two subsidiaries, Myanmar Wanbao Mining Copper, Ltd. and Myanmar Yang Tse Copper, Ltd., as well as King Royal Technologies Co., Ltd., the posting by the U.S. Department of Commerce said.
The listings address foreign policy and national security concerns and support the U.S. efforts "to promote an immediate return to democracy," the posting said.
The three copper mining-related companies have revenue-sharing agreements with Myanmar Economic Holdings Limited, which provides revenue for the country's Ministry of Defense, which was responsible for the military takeover, the posting said.
The listing is an effort to ensure that items subject to U.S. export regulations are not available for copper mining operations by the companies, the Commerce Department said.
King Royal Technologies, a telecommunications company, was added for providing satellite communication services in support of the military, the posting said.
U.S. exports to companies placed on the Commerce Department's trade blacklist, formally known as the entity list, are restricted.
(Reporting by Karen Freifeld and Daphne Psaledakis; editing by Chizu Nomiyama and Philippa Fletcher)