SHANGHAI -- The Shanghai work safety authority has ordered a thorough safety check on small shops and restaurants as well as old buildings in the city following the collapse of a supermarket over the weekend, which killed three and injured six.

The city's safety commission said in a notice Tuesday that part of the JDL Supermarket building in Pudong District collapsed at about 7 a.m. Saturday, killing three people. One of the six injured is still in critical condition.

The commission said the accident exposed safety loopholes in the management and supervision of small restaurants and shops.

It alerted government departments that they should take effective measures to tighten safety supervision, and ordered a cross-sector safety check to investigate the condition of buildings for commercial use.

The overhaul should also target commercial building rentals for multi-layer subcontracts, according to the commission.