A five-storey building in Istanbul has reportedly collapsed, with people believed to be trapped under the rubble.

The building, which is thought to be in the Beyoglu district of the city, appears to be almost completely flattened, with dust and smoke still rising from the remains of the multi-storey structure.

It is not yet known what caused it to collapse, or how many people are thought to be in the building, but photographs of the scene have already been shared on social media.

Fire fighters have been deployed to the scene, Hurriyet Daily News said, as mixed reports came in as to whether the building was occupied or not.

It is believed a coffee shop took up the ground floor of the building, but it is not known how many people - if any- were in there at the time of the building's collapse.