PH issues tsunami warning after magnitude 7.8 earthquake strikes Mindanao

MANILA, June 8 (Reuters) - Tsunami warnings were issued after an earthquake of magnitude 7.8 struck off Mindanao in the southern Philippines on Monday, the German Research Centre for Geosciences said.

The quake struck at a depth of 10 km (6.2 miles), GFZ said. The geophysics agencies of the Philippines and neighbouring Indonesia issued tsunami warnings. There were no immediate reports of major damage in either country.

GFZ had earlier pegged the earthquake at 8.2. The U.S. Tsunami Warning System issued a tsunami threat to the earthquake.

Phivolcs, the Philippine agency, said the quake was magnitude 7.0 and warned of damage and tsunami waves above one metre (yard), which could continue for several hours.

Indonesia's BMKG put the quake at a 7.7 magnitude.

Benjie Ancheta, police chief of Alabel town in Sarangani in the Philippines, said the police building had some cracks immediately after the quake, which occurred during their flag-raising ceremony.

Ancheta said there were no immediate reports of casualties, but some people fainted following the strong tremor.

"This is the strongest earthquake we've experienced," Ancheta told Reuters by phone.

Witnesses in Indonesia's northern city of Manado said the quake felt very strong.

The Philippines and Indonesia are tectonically complex parts of ​the "Pacific Ring of Fire", a seismically active belt stretching from South America to the Russian Far East.

-Reporting by Karen Lema and Mikhail Flores in Manila and Gayatri Suroyo and Fransiska Nangoy in Jakarta and Gnaneshwar Rajan in Bengaluru; Editing by Jacqueline Wong, Tom Hogue and Neil Fullick/Reuters