Britain announced sanctions on Friday against three companies and one individual over what it called the “illicit ‘arms-for-oil’ trade” between Russia and North Korea.

The announcement followed a decision by the United States to impose sanctions on two Russian individuals and three Russian companies for facilitating arms transfers between Russia and North Korea, including ballistic missiles for use in Ukraine.

“The sanctions highlight the joint malign efforts of Russia and the DPRK (North Korea) to circumvent (U.N.) sanctions on petroleum products, which help facilitate the DPRK’s unlawful military programmes,” the government said in a statement.

The statement said Britain was acting “alongside international partners” and quoted Foreign Secretary David Cameron as saying Britain would continue to hold Moscow and Pyongyang to account for such arms transfers.

“Putin is straining every sinew to sustain his illegal war in Ukraine, even resorting to illicit ‘arms-for-oil’ trade deals with the DPRK, blatantly violating UN sanctions that Russia itself voted for, and vetoing UN Monitoring panels that report on their activity,” he said.

Britain said the new sanctions were against Paekyangsan Shipping, which transfers petroleum products between North Korea and Russia, and Toplivo Bunkering Co (TBK) for allowing vessels involved in such transfers to bunker in Russia’s Vostochny Port.

The measures include asset freezes, transport sanctions and travel bans, and also target Russian cargo services provider Vostochnaya Stevedoring Co and TBK Director Aleksey Vorotnikov, it said.

Russian President Vladimir Putin, visiting China, said on Friday that U.S. sanctions policy was undermining confidence in the dollar.