By Simon Lewis and Michael Martina

WASHINGTON (Reuters) – The U.S. is prepared to act against Chinese companies supporting Russia’s war in Ukraine, a senior U.S. official told reporters, highlighting it as an issue Secretary of State Antony Blinken will raise on his trip to China next week.

U.S. officials have warned in increasingly stark terms about what they say is China’s assistance in retooling and resupplying Russia’s defense industrial base after early setbacks in its invasion of Ukraine, saying that continued support is a top risk to stable relations between Washington and Beijing.

Briefing reporters ahead of Blinken’s planned visit to Shanghai and Beijing from April 24-26, the senior State Department official said U.S.-China relations were “in a different place” than a year ago, when ties had sunk to a historic low point after the U.S. downed a suspected Chinese surveillance balloon.

But calmer relations did not mean the U.S. would sacrifice its capacity to strengthen alliances and defend its interests, the official said.

“We’re prepared to take steps when we believe necessary against firms that … severely undermine security in both Ukraine and Europe,” the official said when asked what leverage Washington had to convince Beijing to stop aiding the Russian war effort.

“We’ve demonstrated our willingness to do so regarding firms from a number of countries, not just China,” the official said, noting that Russia had bolstered its weapons-producing capacity with China’s help.

“We will express our intent to have China curtail that support,” the official said.

Blinken’s visit will be his first to China since June, when the United States was trying to restore high-level engagements that Beijing began curtailing after a 2022 trip by then-U.S. House Speaker Nancy Pelosi to Taiwan, the democratically governed island China claims as its territory.

The U.S. has been bracing for Taiwan’s May 20 presidential inauguration and will urge restraint by Beijing even as China’s military has ramped up activity near the island.

“You can expect that the Secretary will underscore both in private and public America’s abiding interest in maintaining peace and stability across the Taiwan Strait,” the official said.

Taiwan’s government rejects China’s sovereignty claims, and the U.S. is the island’s most important international backer despite maintaining only unofficial ties.

Blinken will also raise the crisis in the Middle East, China’s provocations in the South China Sea, the crisis in Myanmar and North Korea’s “threatening rhetoric and reckless actions,” the official said, downplaying the prospect of breakthroughs on any of the issues.

Senior State Department officials – including its top narcotics official Todd Robinson – will join the trip. They are expected to discuss efforts to curb the flow of deadly fentanyl chemicals from China to the U.S.

The U.S. and China launched a joint counter-narcotics working group in January. But a U.S. congressional committee said this week that China’s government was directly subsidizing production of illicit fentanyl precursors for sale abroad and fueling the U.S. opioid crisis.

The official did not answer a question on the alleged subsidies.

China says it is cracking down on fentanyl and precursor chemicals, but it also says the U.S. crisis is a problem of demand, not supply.

Critics in Washington argue the Biden administration has not put enough pressure on Beijing over fentanyl-related substances, which are the leading cause drug of overdoses in the United States.