BBC: Multiple people say they are being forced to quarantine, blocked from public transport or entering buildings. Most appear to be customers of four rural banks which had run into issues providing cash withdrawals, report Chinese media outlets.

The banks froze deposits, prompting angry demonstrations last month.

In many Chinese cities, residents use a "health code" app to enter buildings and shops, use public transport, or leave the city. Users must scan a QR code and show a colour-coded "health status" on their phone before entering.

If this status turns red, it indicates the person has tested positive for Covid recently or is suspected to have Covid, and must be quarantined for 14 days.

On Tuesday, some residents found their status had turned red when they tried to enter train stations, buildings, or hotels. Customers of the four banks who travelled from other provinces to Henan's capital city Zhengzhou have also encountered the same issue.

This is where it's all heading. If you step out of line, we freeze your bank account, code-red you - then code-red your family for good measure.