US Secretary of State Antony Blinken on Friday condemned China's military drills encircling Taiwan as "a significant escalation".
Blinken said there was "no justification" for the exercises launched by Beijing in response to a visit to Taiwan by US House Speaker Nancy Pelosi.
China fired ballistic missiles and deployed fighter jets and warships around Taiwan, declaring multiple no-go danger zones in some of the busiest shipping lanes in the world.
"These provocative actions are a significant escalation," Blinken said after talks with Southeast Asian foreign ministers in Phnom Penh.
Blinken said this week's stand-off was Beijing's latest attempt to alter the fragile status quo over self-ruled Taiwan, which China's ruling Communist Party regards as part of its territory to be recovered, by force if necessary.
He said he had warned Wang Yi at a recent meeting in Indonesia that Pelosi -- the highest-ranking elected US official to visit Taiwan in 25 years -- would likely make the trip to the island.
"We anticipated that China might take steps like this -- in fact we described this exact scenario," Blinken said.
"The fact is, the speaker's visit was peaceful. There is no justification for this extreme, disproportionate and escalatory military response."
He said the United States' position on Taiwan had not changed and it would "not be provoked" by China's actions.
Beijing has insisted its war games are a "necessary" response to Pelosi's visit.
The United States will "pursue" Russia's latest offer to discuss at the presidential level a prisoner swap involving detained basketball star Brittney Griner, Blinken also said Friday.
"[Russian] Foreign Minister Lavrov said this morning... that they are prepared to engage" on a swap for the detained US star, Blinken said at a foreign ministers' meeting in Cambodia. "And we'll be pursuing that."
Moscow's latest offer came a day after the Phoenix Mercury player was sentenced by a Russian court to nine years in a penal colony on a drug smuggling charge.
The arrest and sentencing highlighted Moscow's "use of wrongful detentions to advance its own agenda," Blinken added, slamming the use of "individuals as political pawns".
The verdict and sentence were widely condemned in the United States as unjustified and sparked urgent calls for the US government to bring Griner home.
Griner's trial accelerated in recent days as the United States and Russia discussed a potential prisoner swap that could involve the basketball star.
The White House urged Russia later on Thursday to accept its offer of a deal for the release of Griner and former US Marine Paul Whelan, who was imprisoned on espionage charges.
