Beijing urged Washington on Thursday to stop interfering in China's internal affairs by using Tibet autonomous region-related issues, and warned against the implementation of a new act of the US Congress.

Foreign Ministry spokeswoman Hua Chunying said that China resolutely opposes US President Donald Trump's signing into law on Wednesday the Reciprocal Access to Tibet Act of 2018.

It violated basic rules of international relations and sent "severely wrong signals" to separatist forces advocating Tibetan independence, Hua said.

The law calls for the promotion of access for US diplomats, other officials, journalists and others to Tibetan areas of China. If such access is not provided, then the US may restrict Chinese officials deemed responsible for excluding outsiders' entry into Tibet to enter the US.

"The act will harm Sino-US ties, bilateral communication and cooperation in major areas if it is implemented," Hua said at a daily news conference in Beijing.

The US should recognize the high sensitivity of issues involving Tibet, she said, adding that Tibet affairs are China's domestic affairs, and Beijing will not allow outside interference.

The Tibet autonomous region and Tibetan-inhabited areas in the provinces of Sichuan, Qinghai, Yunnan and Gansu are open to foreign visitors, Hua said. Since 2015, nearly 40,000 people from the US have visited Tibet, she added.

Hua noted that taking into account the special geographic and climatic conditions, it is necessary and understandable for the Chinese government to manage entry of foreigners into Tibet in accordance with the law.

Accusations against China ignore the facts and are full of bias, which cannot be accepted, she said.

China's opening-up will only increase, including for Tibet, Hua said.

"China welcomes more foreigners to visit Tibet for tourism and business, and the policy will not change as long as they abide by Chinese laws and regulations and perform necessary procedures," she added.

The US Senate passed the act on Dec 11 after approval from the House of Representatives in September.

Ruan Zongze, executive vice-president at the China Institute of International Studies, said that it is a common practice for the US to interfere in other countries' domestic affairs while calling itself a "lecturer in human rights".

The act makes irresponsible remarks about China, he said."There should be less conflict or grudges between the two countries, not the opposite," he added.