Shanghai's vice mayor has admitted to shortcomings in the city's handling of its Covid-19 outbreak as a record 23,600 new cases were reported in the last 24 hours, Reuters reports.

Deputy Mayor Zong Ming was speaking after the United States said it was allowing non-essential staff and their families to leave its consulate in the city. Zong praised the support from the public and the work of front line workers despite public criticism of strict curbs but said the handling of the virus needed to improve.

"We feel the same way about the problems everyone has raised and voiced," he told a daily briefing. "A lot of our work has not been enough, and there's still a big gap from everyone's expectations. We will do our best to improve."