Villahermosa, Mexico ? Hurricane warnings were posted Monday 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 hurricane before it makes landfall later this week.

Forecasters said the storm’s path could push oil from the huge Gulf oil spill farther inland and disrupt cleanup efforts.

Alex was swirling through the Gulf of Mexico with winds near 65 mph Monday night on a path that would take it very near the Mexico-U.S. border sometime late Wednesday, said the U.S. National Hurricane Center in Miami. The storm is expected to become a hurricane today.

Conditions late Monday afternoon led the center to believe the storm will be less powerful than previously predicted but still likely to gain hurricane strength, forecaster Todd Kimberlain said.

Tropical storm-force winds extended up to 70 miles from the storm’s center, and Alex was moving toward the north near 5 mph.

Heavy rains in Mexico’s southern Gulf coast state of Tabasco forced the evacuation of about 300 families from communities near the Usumacinta river.

The hurricane warnings extend from Baffin Bay, Texas south across the mouth of the Rio Grande river to La Cruz, Mexico.

The tropical storm’s center wasn’t expected to approach the area of the oil spill off Louisiana’s coast.