Indonesia to keep monitoring for potential tsunami until at least 1435 GMT

Indonesia's geophysics agency said on Friday it would keep monitoring for the risk of a potential tsunami until at least 21:35 pm (1435 GMT) after a powerful earthquake struck off the islands of Sumatra and Java.

Geophysics agency chief Dwikorita Karnawati said residents of coastal areas at risk should continue to stay alert following the tsunami warning.

"Please look for higher ground at least 10 metres (33 feet) high, stay calm and keep monitoring information from the geophysics agency," Karnawati told a news conference.