Friday's action targeted two Singapore-registered companies and a Marshall Islands-registered company, the U.S. Treasury Department said in a statement, as Washington seeks to hold North Korea accountable for ship-to-ship transfers that circumvent United Nations sanctions on the country.

"The DPRK's (North Korea's) long-range ballistic missile launches, including over Japan, demonstrate a continued disregard for United Nations Security Council resolutions," the Treasury's Brian Nelson, Under Secretary for Terrorism and Financial Intelligence, said in the statement.

"The United States will continue to enforce multilateral sanctions and pursue the DPRK's sanctions evasion efforts worldwide, including by designating those who support these activities."

North Korea fired two short-range ballistic missiles into the sea on Thursday in the direction of Japan, after the return of a U.S. aircraft carrier to the region and a U.N. Security Council meeting in response to the North's recent launches.

The missile launch was the sixth in 12 days and the first since North Korea fired an intermediate-range missile (IRBM) over Japan on Tuesday, which prompted joint South Korean and U.S. missile drills during which one weapon crashed and burned.

The Treasury said it imposed sanctions on Singapore-based Kwek Kee Seng, Taiwan-based Chen Shih Huan and Marshall Islands-registered company New Eastern Shipping Co Ltd, accusing them of being involved in the ownership or management of a vessel that has participated in several deliveries of refined petroleum to North Korea.

Also designated were Singapore-registered Anfasar Trading (S) Pte. Ltd. and Singapore- registered Swanseas Port Services Pte. Ltd.

(Reporting by Daphne Psaledakis)

By Daphne Psaledakis and David Brunnstrom