Authorities in Shanghai have said they will tighten the enforcement of lockdown measures, as a Covid surge continues in China's financial capital.

New measures include placing electronic door alarms to prevent those infected from leaving, as well as evacuating people to disinfect their homes.

Earlier this week, hundreds were forcibly evacuated from their homes to allow for buildings to be disinfected.

The restrictions will take Shanghai's lockdown into its fifth week.

Shanghai city officials said all infected patients and close contacts will be transferred to government-run centralised quarantine.

In addition, disinfection measures will be escalated in some of the city's worst-hit areas. This will likely mean some residents will be forced to move out temporarily - including those who have tested negative.

The move comes days after people in two other Shanghai communities - Beicai and Pingwang - were ordered to leave their residences for temporary accommodations.

In Beicai, an official notice issued to residents told them to pack their belongings and leave their wardrobe doors open.

They were also told to leave open the front door of their home and their pets behind. Images on social media of people queuing with packed suitcases at night-time showed the scale of the operation.