BEIJING, May 15 (Xinhua) -- China firmly opposes U.S. interference in China's internal affairs, a Chinese mainland spokesperson said Wednesday.

Ma Xiaoguang, a spokesperson with the State Council Taiwan Affairs Office, made the remarks at a press conference in response to the fact that the U.S. House of Representatives has passed the "Taiwan Assurance Act of 2019" in an attempt to normalize arms sales to Taiwan.

Ma said the U.S. should adhere to the one-China principle and the provisions of the three China-U.S. joint communiques and cease to undermine cross-Strait peace and stability.

"We reassert that the reliance of the Democratic Progressive Party administration on foreign forces won't work," Ma said. "Any attempt that relies on foreigners to build itself up will pay a price for its own deeds."