BEIJING: China said on Wednesday the United States had abruptly told it to close its consulate in the city of Houston, a move that Beijing said it strongly condemns, threatening retaliation.

The United States gave the Chinese side a deadline of three days to close the mission in the Texas city, the Chinese foreign ministry said.

The US State Department said on Wednesday that the recent closing of China's consulate in Houston was to protect Americans' intellectual property and private information.

"We have directed the closure of PRC Consulate General Houston, in order to protect American intellectual property and Americans' private information," State Department spokesman Morgan Ortagus told reporters during US Secretary of State Mike Pompeo's visit to Copenhagen, adding that under the Vienna Convention states "have a duty not to interfere in the internal affairs" of the receiving state.

Relations between the United States and China have deteriorated significantly since the outbreak of the novel coronavirus in the Chinese city of Wuhan at the beginning of the year.

"The unilateral closure of China's consulate general in Houston within a short period of time is an unprecedented escalation of its recent actions against China," Chinese foreign ministry spokesman Wang Wenbin told a regular news briefing.

"We urge the US to immediately revoke this erroneous decision. Should it insist on going down this wrong path, China will react with firm countermeasures," he said.

He also said the consulate was operating normally but did not reply to questions about U.S. media reports in Houston on Tuesday night that documents were being burned in a courtyard at the consulate.

"It appears to be open burning in a container within the courtyard of the Chinese consulate facility. It does not appear to be an unconfined fire but we have not been allowed access," Houston fire department chief Samuel Pena was quoted as saying by KTRK, an ABC television affiliate.

"We are standing by and monitoring."

Houston police told FOX 26 that staff there were burning documents because they are being evicted from the building on Friday afternoon.

The two countries have clashed recently over trade, technology, a national security law imposed on Hong Kong and China's claims in the South China Sea.

Also on Tuesday, the US Justice Department indicted two Chinese nationals for a decade-long cyber espionage campaign in which they were accused of stealing information on weapons designs, drug information, software source code and personal data.