Police have detained a suspect who threatened to blow up a Shanghai bank.

The suspect entered a branch of Citibank, in the city's Lujiazui financial area, on Jan 16 and said they had a bomb.

The emergency services received a call at around 4 pm.

The suspect, who has not been identified, was taken into custody shortly afterwards, police said.

Officers found no explosive device on his or her person.

Calls to the branch, which is housed in the China State Shipbuilding Corp building in Pudong New Area, went unanswered.

A spokesman at the bank's headquarters also declined to comment on the case.

Images of police arriving at the scene and creating a safety zone around the bank quickly spread online on Jan 16 after being uploaded to the Internet.

Police said they are continuing to investigate the case.