Jakarta - A 7.5 magnitude quake struck off Indonesia's Aceh province on Wednesday, the U.S. Geological Survey said, but there were no reports of deaths or casualties and no local tsunami warning was issued.

USGS said the quake's depth was 34 km (21 miles) and occurred at 0808 GMT.

The epicentre was about 310 km south-southeast of Banda Aceh, the provincial capital of Aceh province, which was hit by a devastating tsunami in 2004 that left more than 170,000 dead or missing in Indonesia.

A Reuters witness said strong tremors were felt in Banda Aceh for over a minute, sending people pouring out on the streets in panic.

Indonesia's meteorology and geophysics agency said the quake measured 6.6 on the Richter scale. The agency recorded at least two aftershocks in the same area about 20 minutes after the first tremors, one measuring 5.5 and the other 5.3 on the Richter scale.

Budi Waluyo, the agency's head of early earthquake warning, said the quake was felt strongly in Meulaboh, in Aceh, and Gunung Sitoli on Nias island.

"An earthquake of 6.6 can damage houses," Waluyo told Reuters.

The Hawaii-based Pacific Tsunami Warning Centre issued a tsunami watch for Indonesia but said that a destructive widespread tsunami threat did not exist based on historical earthquake and tsunami data.

Indonesia suffers from frequent earthquakes. The archipelago lies on an area of intense seismic activity where a number of tectonic plates collide.

(Reporting by Adhityani Arga and Fitri Wulandari; Editing by Sugita Katyal and David Fogarty)