The United States has formally labelled the Wagner Group a “transnational criminal organization”, unveiling a wave of sanctions against the Russian mercenary force.

The administration of US President Joe Biden announced the new measures on Thursday as Washington continues its push to penalise Moscow over its invasion of Ukraine.

The “transnational criminal organization” designation brings Wagner under a strict sanction programme by the US Department of the Treasury, freezing the group’s assets in the US and prohibiting American citizens from providing support to it.

The move comes weeks after Washington accused Wagner, which has been active in Ukraine, of buying weapons from North Korea – a claim denied by both Pyongyang and Wagner.

US Treasury Secretary Janet Yellen said Russian President Vladimir Putin has been relying on “the brutal” Wagner Group for support in Ukraine as Washington and its allies ramp up sanctions on Moscow.

“Today’s expanded sanctions on Wagner, as well as new sanctions on their associates and other companies enabling the Russian military complex, will further impede Putin’s ability to arm and equip his war machine,” Yellen said in a statement on Thursday.

The Treasury also imposed sanctions on six individuals and 12 firms – based in Russia, China, the Central African Republic, Luxembourg and the United Arab Emirates – that it accused of links to Wagner and support for Russian defence-related entities.

Last week, the White House said Wagner was committing human rights abuses and engaging in an “ongoing pattern of serious criminal activity”.

The US Department of State also issued sanctions and visa bans against Wagner and other Russian groups and individuals on Thursday.

“This action supports our goal to degrade Moscow’s capacity to wage war against Ukraine, to promote accountability for those responsible for Russia’s war of aggression and associated abuses, and to place further pressure on Russia’s defense sector,” Secretary of State Antony Blinken said in a statement.

Russian businessman Sergei Adonev was amongst those targeted by the State Department, which said it was identifying as blocked property “two yachts and one aircraft” associated with him.

The Biden administration has been piling sanctions against wealthy Russians who support the Putin government. US and European penalties have also targeted various sectors of the Russian economy and technology and security industries.

Russia launched its all-out invasion of Ukraine on February 24 – 11 months ago – after a months-long standoff that saw Moscow amass troops near the Ukrainian borders as Putin demanded an end to NATO expansion into former Soviet republics.

Moscow’s war campaign has been mired by military setbacks, as the US and its Western allies continue to provide financial and military support to Kyiv.

Russia has vowed to resist the sanctions, accusing the West of prolonging the conflict by arming Ukraine, Al Jazeera reports.