Manila, Philippines - Two strong earthquakes rocked the Philippine capital and nearby provinces nearly simultaneously Saturday, but no damage or tsunami alerts were reported, a senior seismologist said.

Renato Solidum, director of the Philippine Institute of Volcanology and Seismology, said a "moderately strong" tremor struck late morning Saturday followed by a "stronger one" five minutes later.

The temblors struck off the coast of Mamburao township in Mindoro Occidental province, about 106 miles south of Manila, Solidum said.

He said the earthquakes would not generate tsunamis because they were centered too deep underground. The first quake had a magnitude 5.3 and was centered 51 miles underground and the stronger magnitude 6.5 was about 67 miles deep.

The U.S. Geological Survey reported the first was magnitude 5.6 and the second was a stronger but deeper magnitude 6.1.

Solidum said seismographs have already recorded some small aftershocks.

The earthquakes were reportedly felt as far as Apalit township in Pampanga province, about 137 miles north of the epicenters, he said. They were also felt in Bataan province west of Manila and Batangas south of the capital.

The Philippine archipelago lies in the so-called Pacific Ring of Fire, where quakes are common.