Police in the Chinese city of Chengdu restricted access to the area around the U.S. consulate on Monday morning, when the United States was believed to be due to exit the premises in retaliation for China being ousted from its Houston consulate.

Four officials in personal protective gear could be seen walking towards the consulate at about 10:24 a.m. local time (02:12 GMT).

China on Friday ordered the closure of the facility after Washington last week gave China 72 hours to vacate its consulate in Houston, in a dramatic escalation of a worsening in relations between the world's two largest economies.

Beijing has not announced the deadline for when the consulate in Chengdu must be shut.

On Friday, the editor of the Global Times tabloid said on Twitter that based on the principle of reciprocity, 72 hours would mean the consulate should be shut at 10 a.m. However, a later post from him said the closure would be on Monday morning.

State broadcaster CCTV shared a video on its Twitter-like Weibo account, taken by a reporter, of the American flag in front of the consulate in Chengdu being lowered at 6:18 a.m. Monday morning.

On Sunday night, a crane could be seen entering the consulate compound and hoisting at least one container onto a large truck.

On Saturday evening, a worker could be seen using tools including a hammer and chisel to remove fittings around a plaque outside the main entrance.

U.S.-China relations have plunged to their worst in decades over a range of disputes, from trade and technology, to the COVID-19 pandemic, China's territorial claims in the South China Sea and its clampdown on Hong Kong.