U.S. plans to further curb the operations of Russia’s so-called “shadow fleet” of oil tankers are unacceptable and its desire to impede Russia-China trade is part of an illegal trade war, Russian Foreign Ministry spokeswoman Maria Zakharova said on Thursday.

White House Deputy National Security Adviser For International Economics Daleep Singh said on Tuesday that the United States and its partners were prepared to use sanctions and export controls to prevent China-Russia trade that threatens their security amid the ongoing Ukraine war.

He said the countries could also further act to increase Russia’s cost of using a “shadow fleet” to evade the Group of Seven countries’ oil price cap.

Responding to Singh’s statement, Zakharova said U.S. efforts to disrupt Russia-China trade and its frequent and “uncontrolled” use of sanctions was not only failing but also undermining the global financial system.

“We see this as interference in trade and economic relations between other countries. We can qualify this as a trade war against our country,” Zakharova told a news briefing.

“U.S. threats will not force our country to abandon its trade and economic relations with partners … including with China, which are in full compliance with international law.”

She said Western efforts to make it harder for Russia to deliver seaborne oil exports were undermining global energy security, accelerating market fragmentation, and increasing inflationary pressures.

“We categorically reject attempts to interfere in the functions of the world’s energy markets,” Zakharova said.

“We strongly condemn the introduction of price caps, restrictions on oil sales, attempts to set up buyers’ cartels and demands to lower the prices.”

The fleet of ageing tankers has helped Moscow transport Russian cargoes as well as oil from Iran and Venezuela, countries also contending with Western sanctions.

The G7 group of industrialised nations approved a price cap of $60 per barrel for Russian oil after Washington lobbied to curb the Kremlin’s revenue amid the conflict with Ukraine while keeping Russian oil flowing to avoid an energy price spike.

Supplies of Russian energy resources to the countries of the Global South were sustainable, Zakharova said, suggesting Washington was uneasy about the situation.

“We supply to anyone who wants it with whom we agree on a price. For us, it is free-market relations, relations of mutual acceptance and trade co-operation,” she said.

Source: Reuters reported by Dmitry Antonov and written by Vladimir Soldatkin and Andrew Osborn and edited by Jason Neely and Alison Williams