Undated (AP) _ Lightning struck four people huddled under an umbrella on the beach in Maryland on Sunday, killing three and critically injuring the fourth, while lightning killed two teen-agers under a huge oak tree in Alabama.

The three killed in Ocean City, Md., were identified as Sonia Hernandez, 30, of Arlington, Va.; Jose Sontos Ortiz, 19, of Washington; and Delfin Cedillo, 20, of Washington.

An unidentified 55-year-old man was in critical condition at Peninsula General Hospital in Salisbury, said Ocean City police spokesman Jay Hancock.

A fifth person, a vendor of beach chairs, was being treated in the emergency room at Peninsula General Health Services, Hancock said, adding that he didn't know where the vendor was when he was struck.

In Mobile, Ala., the teen-agers had taken refuge under the tree from the storm Saturday afternoon.

''It was not a dead hit but close enough,'' said Gary Cumberland, a state pathologist.

The victims, identified as Antonio Singleton, 17, and Gregory Ropert, 16, suffered burns and other injuries, he said. Singleton was pronounced dead on arrival at a hospital and Ropert died early Sunday, said Cumberland.