Four Republican and Democratic US senators have introduced legislation to discourage Taiwan's few remaining allies from switching their allegiance to China, after El Salvador and Beijing established diplomatic relations late last month.

The legislation, introduced by Republican senators Cory Gardner and Marco Rubio and Democrats Ed Markey and Bob Menendez on Monday, would authorize the US State Department to downgrade US relations with any government that shifts away from Taiwan, and to suspend or alter US assistance, according to a news release posted on Senator Gardner's official website on Wednesday.

The legislative attempt came two weeks after El Salvador severed its so-called diplomatic ties with Taiwan and established diplomatic relations with China on Aug 21.

There was no immediate comment on the proposed legislation from China's Foreign Ministry by press time.

On Aug 23, Gardner, chairman of the Senate Foreign Relations Committee's Asia subcommittee, told Reuters that he would introduce within a few days a measure encouraging countries to stick with Taipei.

The next day, at a regular news conference in Beijing, China's Foreign Ministry spokesman Lu Kang was asked about the legislative efforts of an unidentified US senator.

"We hope that the relevant country can respect other sovereign states' right to choose and formulate their foreign policies and stop interfering in other countries' domestic affairs," Lu said.

Lu said that while some US politicians are making these "jarring noises" on the establishment of diplomatic ties between China and El Salvador, the president and government of El Salvador have made public statements, declaring that their decision meets the trend of the times and the fundamental interests of the Salvadoran people.

"I am convinced that the Salvadoran people know best what is in their own interest," Lu said.

Lu also said earlier that there is only one China in the world. The government of the People's Republic of China is the sole legal government representing the whole of China, and Taiwan is an inalienable part of China's territory.

"This is a historical fact and a well-recognized norm governing international relations," Lu said on Aug 21.

El Salvador is the 26th nation in the Americas with which China has forged diplomatic relations, including the United States.

Jon Taylor, a professor of political science of the University of St. Thomas in Houston, said it is "a little bit comical" for the US to issue threats of punishment toward nations for doing what the US did in 1979: recognize the People's Republic of China and endorse the One-China Policy.

"The small Central American nations that the legislation is aimed at might be quite resentful of US interference," Taylor told China Daily.

"They may, in fact, see the US's threat to punish them for something that most of the world has already done as rank political hypocrisy," he said.

Contact the writer at huanxinzhao@chinadailyusa.com