China ordered the United States to close its consulate in the city of Chengdu on Friday, responding to a US demand this week that China close its Houston consulate, as relations between the world's two largest economies deteriorate.

The order to close the consulate in Chengdu, in southwestern China's Sichuan province, was seen as roughly reciprocal in terms of scale and impact, continuing China's recent practice of like-for-like responses to US actions.

China had warned it would retaliate after it was unexpectedly given 72 hours — until Friday — to vacate its Houston consulate, and had urged the US to reconsider.

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“The US move seriously breached international law, the basic norms of international relations, and the terms of the China-US Consular Convention. It gravely harmed China-US relations,” China's foreign ministry said in a statement.

“The Ministry of Foreign Affairs of China informed the US Embassy in China of its decision to withdraw its consent for the establishment and operation of the US Consulate General in Chengdu,” it said.

The US Department of State and the US embassy in Beijing did not immediately respond to requests for comment.

Foreign ministry spokesperson Wang Wenbin said some Chengdu consulate personnel were “conducting activities not in line with their identities” and had interfered in China's affairs and harmed China's security interests, but he did not say how.

The consulate was given 72 hours to close, or until 10am on Monday, the editor of the Global Times newspaper said on Twitter.

The consulate opened in 1985 and has almost 200 employees including about 150 locally hired staff, according to its website. It was not immediately clear how many are there now after a significant number of US diplomats were evacuated from China during the early stages of the novel coronavirus outbreak.

Global share markets fell after the announcement, led by a heavy drop in Chinese blue chips, which fell 4.4 per cent, while the yuan hit a two-week low.

The US State Department warned American citizens in China of a greater risk of arbitrary law enforcement including detention and a ban on leaving, repeating a similar warning two weeks ago.

Troubled ties

Relations between Washington and Beijing have deteriorated sharply this year over a range of issues, from trade and technology to the novel coronavirus, China's territorial claims in the South China Sea and its clampdown on Hong Kong.

US Secretary of State Mike Pompeo said in a speech on Thursday the US and its allies must use “more creative and assertive ways” to press the Chinese Communist Party to change its ways, calling it the “mission of our time”.

A source had previously told Reuters that China was considering shutting the US consulate in Wuhan, where the US withdrew staff early this year as the coronavirus outbreak raged.

A state newspaper editor had suggested that China could order a dramatic scale-back of staff at the US consulate in Hong Kong.

“The Chengdu consulate is more important than the Wuhan consulate because that is where the US gathers information about Tibet and China's development of strategic weapons in neighbouring regions,” said Wu Xinbo, a professor and American studies expert at Fudan University in Shanghai.

He said the Chengdu consulate was less important for trade and economic activity than US consulates in Shanghai, Guangzhou and Hong Kong.

The Chengdu consulate became notorious in 2012 when Wang Lijun, the police chief of nearby Chongqing city, attempted to defect there, a trigger point in a dramatic scandal that brought down rising political star Bo Xilai.

Chinese social media users, who had denounced the US order to close the Houston mission, applauded the response.

The comment, “let's renovate it into a hotpot restaurant!”, a reference to a popular dish in Chengdu, got 100,000 likes on the Weibo account of state broadcaster CCTV.