A powerful earthquake struck off the southern coast of Indonesia's heavily populated Java island Friday, with the country's disaster agency warning that it could generate a tsunami of up to three metres.
The 6.9 magnitude quake hit at a depth 52.8 kilometres, some 150 kilometres from Labuan, southwest of the capital Jakarta, according to the United States Geological Survey (USGS). 
The USGS initially put the quake's magnitude at 6.8 and a shallower depth before raising its intensity.
Indonesia's disaster agency pegged the quake at magnitude 7.4 and warned it could spark a tsunami.
"There are some areas at risk of a serious threat of a tsunami that could be as high as three metres," said agency official Rahmat Triyono.
"We're still waiting for reports about damage," he added.
There were no immediate reports of casualties.
The agency said a tsunami could strike the Sunda Strait, between Java and Sumatra islands, where a December volcano-sparked tsunami killed over 400 people.
It also called for people living in high-risk areas along the coast to evacuate to higher ground. 
"For places with a lower tsunami risk we're still asking people to avoid the coast," said disaster agency spokesman Agus Wibowo.
The agency said it would lift the tsunami warning around 9:35 pm local time (1435 GMT) if there was no sign of a quake-sparked wave.
Residents in Jakarta fled their homes as buildings in the megacity swayed from the force of the quake, which struck at 7:03 pm (1203 GMT).
"The chandelier in my apartment was shaking and I just ran from the 19th floor," 50-year-old Elisa told AFP. 
"Everybody else ran too. It was a really strong jolt and I was very scared."
At least five people were killed and thousands were forced from their homes after a major 7.3-magnitude earthquake hit the remote Maluku islands in eastern Indonesia last month.
Indonesia experiences frequent seismic and volcanic activity due to its position on the Pacific "Ring of Fire", where tectonic plates collide.
Lombok, next to holiday hotspot Bali, was rocked by earthquakes last summer that killed more than 500 and sparked a mass exodus of foreigners from the tropical paradise.
Also last year, a 7.5-magnitude quake and a subsequent tsunami in Palu on Sulawesi island killed more than 2,200 people, with another thousand declared missing.
On December 26, 2004, a devastating 9.1-magnitude earthquake struck off the coast of Sumatra and triggered a tsunami that killed 220,000 across the Indian Ocean region, including around 170,000 in Indonesia. 
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