Crowds of people had gathered near the consulate, which is surrounded by community compounds and commercial buildings. Many were taking photos of blocked roads and the assembled people, while two of the several police officers guarding the roads patrolled nearby.

There was no sign of movement at the compound until shortly before 11 am when several cars, a white ambulance, and dozens of Chinese workers were seen leaving, as people lingered nearby.

Several side streets, as well as a main road leading to the consulate were blocked, with dozens of policemen guarding the intersections. At 6.24am, the US national flag was lowered from the flagpole inside the compound for the last time.

Ellen Hu, a 30-year-old Chengdu resident among the crowd, said her office opened at 9.30am, but she had decided to wait until 10am to see the closure of the consulate. “To witness the closure is more important,” she said. “It only happens once in decades.”

Late on Sunday night, three semi-trucks and a crane truck entered the compound, guided by a handful of workers standing near the gate.

The consulate, which opened in 1985, has almost 200 staff, including about 150 locally hired employees, according to its website.

There was a festive atmosphere outside the building almost as soon as the closure was announced on Friday.

People gathered to take selfies, photos and videos, with some travelling from across China to witness the historic event.

Sales doubled at an ice jelly stall opposite the consulate, according to one of its employees, surnamed Tang. “I can sell about 300 bowls of ice jelly now,” she said.

“People have even flown from Xian [in the northwest] or Hainan [China’s southernmost island] to be part of this event.”

One ice jelly customer, Xu Junqing, 60, from the northern province of Hebei, said he had been visiting his son in Chengdu last week and had come to the consulate on Saturday and Sunday.

“I think most people are just curious. But I think it will reopen again, because if China and the US stop cooperation, there’s no good to the whole world.”

Jolin Wang, a 26-year-old employee at a Chengdu education institute, said she had been at the consulate each day since Friday’s announcement, armed with an umbrella and a telescope.

“It’s a matter of international concern and it just happened near me, so I want to know every step of the process.”

Wang said she planned to return to the consulate on Monday afternoon to see if Chinese officials would enter the compound, in the same way US officials had done at China’s diplomatic office in Houston.

The tit-for-tat consulate closures have accelerated a sharp deterioration in relations between the two countries, but experts said their relationships could worsen further.

Shi Yinhong, a professor of international relations at Renmin University, said the possibility could not be ruled out that the US would act against China’s consulate in San Francisco where a Chinese researcher – alleged to belong to the People’s Liberation Army – had been in hiding, according to American authorities.

She was arrested and booked at the Sacramento County Jail early on Friday morning.

“The US has made up its mind to deal with China in all aspects,” Shi said. “So in the following six months, until the new president moves into the White House, the possibility of further law enforcement against China, including on infiltration and intelligence activities, cannot be underestimated.”

Shen Dingli, a professor at the Institute of International Studies at Fudan University, said China-US relations would keep deteriorating and the US presidential election would accelerate the downward spiral.

“The two countries are having a deep decoupling and it’s even possible for them to break diplomatic relations,” he said. “It was impossible before because of globalisation but now the two countries are dramatically distancing from each other.”