The Biden administration is cautioning China to “exercise restraint” after the Chinese military conducted provocative military drills near Taiwan on Friday.

Dozens of Chinese navy vessels and warplanes were sighted off the coast of Taiwan on Friday, according to 49 Chinese warplanes and 19 navy vessels were counted in total.

Taiwanese officials reported that 35 of the Chinese planes crossed the median line in the Taiwan Strait, which is considered the de-facto boundary between the two countries.

In a statement released on Saturday, spokesperson Matthew Miller said that the U.S. is “deeply concerned” over the military drills.

“We are monitoring PRC activities closely and consulting with allies and partners on our shared concerns,” the statement read. “We strongly urge Beijing to exercise restraint.”

“Using a normal, routine, and democratic transition as an excuse for military provocations risks escalation and erodes long-standing norms that for decades have maintained peace and stability across the Taiwan Strait, which is crucial for regional and global security and prosperity and a matter of international concern,” Miller added.

On Friday, Chinese Foreign Ministry spokesperson Wang Wenbin criticized the U.S.’s prior calls for restraint in response to previous military drills.

“[The U.S.] is not in a position to make such irresponsible remarks,” Wang was quoted as saying.

The drills coincide with escalating tensions in the area. Former Taiwanese navy captain Lu Li Shih told Sky News that China is “preparing for war.”

“China is preparing for war based on the number of military ships and the hiring of new recruits. It’s all for self-defense, and Taiwan,” the former captain said.