MEXICO CITY - The Mexican Navy searched for sharks in the ocean near Pacific surfing beaches on Monday, after two bathers were killed and another maimed in a rare spate of shark attacks.

Three boats and a helicopter patrolled the sea while Navy and rescue officials scanned the horizon with binoculars from popular beaches around the southwestern Mexican resort of Ixtapa-Zihuatanejo. They warned surfers not to go far out.

"We've been monitoring the beaches; we've done reconnaissance flights," Rear Adm. Arturo Bernal said, adding that no big shark had been detected yet in the area.

Surfer Bruce Grimes from Texas was bitten on the arm on Saturday off nearby Playa Linda beach, making him the third target of a shark attack in the area in a month.

Two attacks in April and May killed a Mexican and an American -- the first shark deaths off Mexico's Pacific coast in 30 years, according to official records.

Grimes, 49, said he paddled madly toward shore on his board after feeling the unmistakable sandy skin of a shark glide across the bottom of his feet as he straddled his surfboard.

"Then it bumped me really hard. I thought, 'That's definitely a big shark.' I took about three more strokes and he grabbed my arm," said Grimes, who pulled himself free and made it to the beach. He managed to drive himself to a hospital, where he received 100 stitches.

On Friday, Mexican surfer Osvaldo Mata, 21, died after a 6-foot-long (2-m-long) shark seized him, bit off one of his hands and chomped on his thigh. That followed the death in late April of a 24-year-old American who was mauled while surfing nearby.

The Ixtapa-Zihuatanejo government is consulting with experts to determine what could be causing the attacks.