A strong 7.3 earthquake shook an area in the Pacific Ocean off the coast of El Salvador early Monday, U.S. officials said, triggering a brief tsunami alert for Central America and Mexico.

The warning was quickly canceled without indication whether the tidal wave had caused any damage.

The Secret Service said Thursday it is investigating explosive new allegations of misconduct in El Salvador, broadening a sex scandal that a U.S. lawmaker said may lead to changes in how agents do their work abroad.

A CBS broadcast affiliate in Seattle aired new accusations emerging from the Central American nation, where members of a presidential advance team one year ago reportedly were seen by a government subcontractor paying for sex at a strip club and taking escorts back to their hotel rooms.

Some 11.5 million foreigners are living in the United States without proper immigration documents, according to estimates released Friday by the U.S. Department of Homeland Security.

The figures, as of January 2011, show little difference from the 11.6 million figure published in 2010.

A 6.2 magnitude earthquake struck near Mexico's southern coast on Saturday, U.S. Geological Survey seismologists said, but initial reports indicated there were no injuries.

The quake occurred at a depth of 66 kilometers some 57 kilometers southwest of Mapastepec, in Chiapas state, and was felt as far away as San Salvador, the capital of El Salvador.

Heavy rains pounded Central America on Tuesday, where more than 80 people have died in mudslides and flooding over the past week as swollen rivers destroyed bridges and submerged roads.

Authorities have gone on high alert across the mountainous region, home to 42 million people, as the rains have shown no sign of abating.