MEXICO CITY (AP) _ The first Atlantic hurricane this year continued to intensify in the Gulf of Mexico today and could threaten the coasts of Mexico and Texas early next week.

Hurricane Bret was located about 280 miles southeast of Brownsville, Texas, at 5 a.m. EDT and heading north-northwest at 7 mph, the U.S. National Hurricane Center in Miami reported.

A hurricane watch was in effect from Tuxpan, Mexico northward to Baffin Bay, Texas. All watches and warnings were discontinued south of Tuxpan. The center said ``the Texas coast should closely monitor'' the hurricane's progress over the weekend.

Maximum sustained winds were near 90 mph, with higher gusts. Additional strengthening of winds is expected in the next 24 hours.

The center said that the heaviest rains associated with the hurricane would likely remain offshore today.

James Franklin, a hurricane specialist at the center, said his ``best guess'' is that it will reach the Mexican coast, probably on Monday.

``Of course, there's enough uncertainty in the forecast,'' he said. If the storm doesn't start moving west, it may not strike land until it crosses the border into Texas.

The storm is expected to continue building strength over the weekend. The forecast for Sunday is for sustained winds of 98 mph.

A hurricane watch was in effect from the coastal town of La Pesca, 350 miles north of the Gulf port city of Veracruz. Area residents were told to expect as much as five to eight inches of rain, beginning as early as today. Some showers were nearing the southern Texas coast.

In the northern coastal state of Tamaulipas, which includes Tampico, a state of alert was declared along the coast and a state official, Vladimir Martinez Ruiz, announced that 500 shelters are being prepared in case residents are forced to leave their homes, the government news agency Notimex reported.

In Veracruz state, Gov. Miguel Aleman also ordered that all schools be available for use as emergency shelters.