Updated

MEXICO CITY (AP) — Mexican officials fear the Gulf oil spill could reach their coasts if the leak is not stopped by August, when seasonal currents start to reverse and flow south. They also worry about the impact of the upcoming hurricane season.

So far prevailing currents have carried at least 4 million gallons of spilled oil from a damaged BP well toward the north and east, away from Mexico and toward U.S. shores.

But those currents start to shift by August, and by October the prevailing currents have reversed toward Mexico.

Carlos Morales, the head of exploration and production for the state-owned Petroleos Mexicanos oil company, said Wednesday that if efforts to quickly block the leak with new valves or other devices fail, it could take four to five more months to drill another well that would relieve the pressure fueling the leak.

"That is the range we are talking about, from a week or two to four to five months," Morales said at a news conference.

He added that Mexico has sent several thousand meters (yards) of containment booms to the United States to help fight the spill. He said Mexico has about 120 official vessels in the Gulf that could participate in containment efforts if needed.

Environment Secretary Juan Rafael Elvira Quesada also told local media that officials are concerned the hurricane season — which begins in the Atlantic on June 1 — could potentially stir up or spread the oil slick farther.

Mexico's government is particularly worried about the potential impact on coastal lagoons along Mexico's northern Gulf coast.

At least two species of sea turtles could be severely affected, including the endangered Kemp's Ridley sea turtle, said the head of Mexico's governmental biodiversity council, Jose Sarukhan.

"This is potentially a big problem ... because of the size of the (turtle) populations and their susceptibility to damage," he said.

Mexico's Defense and Environment departments and the state oil company are carrying out a three-day drill of oil spill contingency procedures that concludes Thursday. The drills include containing and collecting simulated spills and helping affected wildlife.

An April 20 explosion on BP's deepwater oil rig killed 11 men and unleashed a powerful gusher.

On Tuesday, Elvira Quesada said that BP must be held responsible for the spill and that his staff is researching international environmental law to see what legal actions it might take.

"It is important and necessary that such errors, omissions, accidents, do not go unpunished," he said. "The biodiversity that is affected is a biodiversity that is common to all beings on the planet."