Foreign Ministry spokesman Lu Kang said on Friday at a daily news conference that the bill violated the basic rules of international relations, and China has lodged solemn representations to the United States.

The Reciprocal Access to Tibet Act of 2018, passed by the US Senate on Tuesday, demands that China grant access to US diplomats, journalists and tourists to Tibet. It also threatens to bar from the US any Chinese officials deemed responsible for what it suggested was an exclusionary policy.

"We urge the US administration to immediately take effective measures to prevent the bill from being signed into law, so as not to seriously damage Sino-US relations and bilateral cooperation in important areas," Lu said.

He said that Tibet affairs are China's domestic affairs and that China will not allow outside interference.

Foreigners can get access to Tibet through regular channels, he said, adding that a large number of Chinese and foreigners visit the region for both leisure and business every year.

Since 2015, nearly 40,000 people from the US have visited Tibet, including senior US politicians, Lu said, adding that accusations against China are untenable and cannot be accepted by the Chinese government and people.

Li Haidong, a professor of US studies at China Foreign Affairs University, said the bill's passage demonstrated that the US government has stepped up hardline policies toward China.

"Such long-arm jurisdiction practices undermine China's sovereignty," Li said.