TEMECULA, Calif. (AP) - A moderate earthquake struck early Monday in a remote area of the Cleveland National Forest in northern San Diego County.

There were no reports of damage or injury.

The magnitude-4.1 temblor struck at 4:35 a.m. about 10 miles north of the Palomar Observatory and about 20 miles east of the Riverside County community of Temecula, according to the U.S. Geological Survey.

It was followed by a magnitude-3.8 aftershock five hours later, the USGS said.

The observatory was closed when the quake struck.

"We gave the place a once over," said spokesman Scott Kardel. "It doesn't look like there was any damage at all."

The quake was felt from San Diego to Palm Desert, said Caltech seismologist Anthony Guarino.