Two moderate earthquakes jolted southern Mexico Tuesday, prompting the evacuation of several buildings in the capital, but there were no immediate reports of damage or casualties, authorities said.

The epicenter of both the initial quake and a smaller aftershock -- which struck shortly after 6:00 am (1300 GMT) -- was located about 15 kilometers (10 miles) west of Pinotepa Nacional, in Oaxaca state.

The first quake had a magnitude of 5.5, while the second measured 5.1, according to the US Geological Survey. Mexico's National Seismology Service put the quakes at 5.6 and 5.4 on the Richter scale.

"Everything is calm following the two earthquakes... no damage, the alerts were activated and trains were stopped, but service has already resumed," Mexico City mayor Miguel Angel Mancera told the Televisa network.

The quakes were felt 350 kilometers (220 miles) away in the capital, and a few buildings were evacuated as a precaution, he said, noting that experts checking the area by helicopter did not see anything amiss.

Authorities in Oaxaca state did not immediately report any damages or casualties.

A strong 6.2-magnitude earthquake struck Guatemala on Monday, and was felt in southern Mexico.