China expressed strong objections on Tuesday to a bill in the United States Senate that would threaten higher tariffs on some Chinese goods in response to what the bill’s sponsors call China’s policy of keeping its currency artificially depressed to give its exports a price advantage.

The Chinese objections came as the Senate began debate on the bill, which would require the Treasury Department to determine whether China is manipulating its currency and then order the Commerce Department to impose tariffs on certain Chinese goods.

Ma Zhaoxu, a spokesman for the Chinese Foreign Ministry, said the bill “seriously violates rules of the World Trade Organization and obstructs China-U.S. trade ties.” The statement, reported by Xinhua, China’s official news agency, urged senators to “rationally understand Sino-U.S. trade cooperation, which is mutually beneficial in nature, and stop pressuring China through domestic lawmaking.”

The statement did not specify what steps, if any, China might take if the legislation were to pass. But Mr. Ma said the bill would “further escalate the exchange rate issue by adopting protectionist measures with an excuse of ‘currency imbalance.’ ”