Zhang Yongzhen, a virologist, said in an online post on Monday that he and his team had been given a sudden eviction notice from their lab, and guards had barred him from entering it over the weekend. The post, published on Weibo, was later deleted, Associated Press (AP) reported.

Zhang has been sitting outside the lab since Sunday. Photos posted online show a man purported to be Zhang sleeping on the ground.

Zhang published his scientific findings about Covid-19 without government approval in January 2020. He and his team have since been subject to a series of setbacks, demotions and oustings, of which the eviction appears to be the latest.