A 6.1-magnitude earthquake has struck the Indonesian island of Java, causing buildings to sway in the capital, Jakarta, officials have said.
The epicentre was located 180km (115 miles) west of the city, in the Sunda Strait, at a depth of 50.6 km (31.4 miles), the US Geological Survey said.
There have so far been no reports of any damage or casualties.
A more powerful 7.6-magnitude quake devastated western Sumatra last month and left more than 1,100 people dead.
An official at the Indonesian Agency for Meteorology, Climatology and Geophysics, Suharjono, told the AFP news agency that Friday's tremor was the result of movement in the same tectonic plate, but that it was impossible to say whether the two events were related.
"However, the epicentres are in the same bloc... due to a clash between the Indo-Australian and Euro-Asian plates," he said.
Suharjono said the quake was not strong enough to cause a tsunami.
In Cilegon, on the western coast of Java, residents said the earth had shaken powerfully and some people had run from their homes, but that there was no evidence of major damage.
"There was strong shaking for less than a minute. There was a lot of panic," Warca Dinata, a teacher, told AFP. "We all ran out of our homes but now everything is OK."
Indonesia sits on the so-called "Pacific Ring of Fire", one of the most active areas for earthquakes and volcanic activity in the world.