"There is no potential for a tsunami," a staff member at the Meteorology and Geophysics Agency, who did not identify himself, told AFP from Indonesia's capital Jakarta.

A 6.3-magnitude earthquake hit under ground on Sumatra on Tuesday, killing at least 52 people and injuring many others.

The new tremor was felt on Sumatra, the Jakarta-based seismologist said.

"It was felt quite strong, people ran out of their houses, but we have earthquakes quite often, so people went back to their houses after it stopped," Siregar, a resident on nearby Nias island, told Elshinta radio.

The quake occurred at 5:53 pm (1053 GMT) and was centred underwater some 105 kilometres (65 miles) west-northwest of Sibolga, Sumatra, the US Geological Survey said. It struck at a depth of around 30 kilometres.

Indonesia, an archipelago of some 17,000 islands, sits on the so-called Pacific Ring of Fire, where continental plates meet -- and where earthquakes are a regular and often deadly occurrence.

The devastating Asian tsunami in 2004 was set off by a massive earthquake off the coast of Sumatra, killing some 168,000 people in Aceh province on its northern tip. A total of 220,000 people died across the Indian Ocean region.