Strong earthquake strikes Indonesia's main island

A tsunami alert was issued, but revoked less than an hour later.

The quake struck at 2:55 pm (local time) on the southern coast of the main island of Java with a preliminary magnitude of 7.0. It had a depth of around 50 kilometres, the US Geological Survey said.

The Pacific Tsunami Warning Center said it was powerful enough to cause a local tsunami, but there were no immediate reports of high waves. Less than an hour later it said in a statement that "sea level readings indicate a significant tsunami was not generated" and retracted the alert.

Buildings in Tasikmalaya, one of the towns closest to the epicentre, were damaged, the Detik.com news portal reported.

There were no immediate reports of injuries.

In the town of Bandung, about 100 kilometres from the epicentre, students fled outdoors when their classrooms began shaking violently, student Leslie Lai told The Associated Press.

The shaking was also strong around 200 kilometres north of the epicentre in the capital, Jakarta, where panicked office workers ran onto the streets.