Washington’s latest sanctions announcement comes as US President Joe Biden attends the G7 summit in Italy.

The United States has rolled out new sanctions against more than 300 individuals and firms accused of aiding Russia’s war effort in Ukraine, including entities in China, South Africa, the United Arab Emirates and Turkey.

US Treasury Secretary Janet Yellen said on Wednesday the measures target Moscow’s remaining avenues for obtaining materials and equipment needed to sustain the war.

“We are increasing the risk for financial institutions dealing with Russia’s war economy and eliminating paths for evasion, and diminishing Russia’s ability to benefit from access to foreign technology, equipment, software, and IT services. Every day, Russia continues to mortgage its future to sustain its unjust war of choice against Ukraine,” Yellen said in a statement.

In remarks carried by Russia’s state-run TASS news agency, Ministry of Foreign Affairs spokeswoman Maria Zakharova said Moscow would “not leave such aggressive actions without a response”.

The targeted entities include the Moscow Exchange, which runs Russia’s largest public markets for equities and foreign exchange products, UAE-based firm Red Coast Metals Trading, and Chinese companies Hangzhou Keming Intelligent Technology and Shandong Oree Laser Technology.

White House national security spokesman John Kirby earlier in the week told reporters that Washington would “confront China’s non-market policies that are leading to harmful global spillovers”.

China has forged closer ties with Russian President Vladimir Putin since the invasion of Ukraine, but has repeatedly denied supplying weapons to Moscow.

Under the latest measures, Washington will also broaden its definition of “military-industrial base” to apply so-called secondary sanctions to foreign financial institutions that do business with any sanctioned entities.

The US Department of Commerce separately announced that it had blacklisted eight addresses in Hong Kong in a bid to disrupt shell companies believed to be diverting semiconductors to Russia.

The announcement of the latest sanctions came as US President Joe Biden arrived in Italy to take part in the annual G7 summit.

The summit, which gathers the leaders of major economies including the United Kingdom, France, Germany and Japan, is expected to focus on ways to bolster support for Ukraine and bring about a ceasefire in Gaza.