The United States on Thursday announced additional sanctions aimed at Russia over its continuing support for Ukraine's rebels and the 2014 annexation of Crimea.

The Treasury Department said in a statement that it had designated 37 new individuals and companies operating in Crimea and Ukraine for the sanctions list.

"Russia continues to provoke instability in eastern Ukraine despite its Minsk commitments," said John Smith, acting director of the Treasury's Office of Foreign Assets Control, in charge of levying sanctions.

"Treasury stands with our partners in condemning Russia's violation of international law, and we will continue to sanction those who threaten Ukraine's peace, security and sovereignty," he said.

According to the Treasury, the move followed the recent extension of European Union economic sanctions, and that together these steps demonstrated "continued international unity in opposing Russia's actions in Ukraine."

Russian companies, including construction firms PJSC Mostotrest and SGM-Most, were added to the U.S. list for their assistance in construction of a bridge from Russia to the Crimean Peninsula.

Russian engineering firm OMZ OAO was sanctioned for its connections to Gazprombank, which was itself sanctioned in 2014.

Several subsidiaries of Russian gas giant Gazprom were also added to the sanctions list.

Newly listed was CJSC ABR Management, an asset management firm closely linked to already-sanctioned Rossiya Bank, often called the personal bank of President Vladimir Putin and members of his closest circle.

Six officials of the self-proclaimed pro-Russian Donetsk People's Republic and Luhansk People's Republic in eastern Ukraine were entered into Treasury's list as well.

The U.S. also sanctioned 11 Crimean officials, including top ministers.

Russian officials have said in the past that sanctions levied over its actions in Ukraine have undermined efforts to resolve the conflict.