VILLAHERMOSA, Mexico – Hurricane watches are in effect for a stretch of Gulf coast in southern Texas and northern Mexico as Tropical Storm Alex gained strength and appeared on track to become a Category 3 hurricane before it makes landfall later this week.

Forecasters said the storm's path could push oil from the massive Gulf oil spill farther inland.

Alex was swirling through the Gulf of Mexico with winds of 60 mph (on a path that would take it very near the Mexico-U.S. border sometime Thursday, said the National Hurricane Center in Miami, Florida. The storm is expected to become a hurricane Tuesday, and could build winds as high as 120 mph by Wednesday.

The hurricane watches extended about 225 miles south of the U.S. border over an area of sparsely populated Mexican coast, and about 100 miles north along the Texas coast from the Rio Grande to just south of Baffin Bay.

The tropical storm's centre wasn't expected to approach the area of the oil spill off Louisiana's coast, said Stacy Stewart, senior hurricane specialist at the National Hurricane Center. But Alex's outer wind field could push oil from the spill farther inland and hinder operations in the area, Stewart said.

Alex caused flooding and mudslides that left at least four people dead in Central America over the weekend, though Belize and Mexico's Yucatan Peninsula appeared largely unscathed.

It made landfall in Belize on Saturday night as a tropical storm and weakened into a depression on Sunday as it crossed the Yucatan Peninsula.

Mexico's northern Gulf coast state braced for heavy rains, and forecasters said precipitation from Alex will keep falling on southern Mexico and Guatemala until Tuesday, raising the possibility of life-threatening floods and mudslides.