WEST PALM BEACH, Fla. — A gunman dressed in a suit and tie burst into a Wendy's restaurant at lunchtime Monday, killing one person and himself and injuring five others, officials and witnesses said.

The gunfire sent customers scampering out of the restaurant. Motorists at the drive-thru window also fled, some leaving their vehicles running.

Palm Beach County sheriff's spokeswoman Teri Barbera said three of the survivors were in critical condition. Two others had minor injuries, including one person who was injured while running away.

Several people were carried from the restaurant on stretchers. Authorities did not identify the shooter or the victims.

"I just saw a lady with a little boy in her arms come running out screaming, 'Somebody's shooting!"' said Sandra Jackson, who had been getting gas across the street. The woman said her husband was still inside, said Jackson, 43, of Palm Springs.

The mayhem unfolded just after noon during the lunch hour rush at the eatery on a major suburban road lined with strip malls, car dealerships and fast food restaurants, about five miles from downtown West Palm Beach. A billboard advertising an upcoming gun show stands just behind the Wendy's.

The shooter entered the restaurant and went to a restroom before coming out brandishing what appeared to be a 9 mm handgun, sheriff's spokesman Paul Miller said.

Ashley Milton, 28, said she had just opened the door to get lunch when she heard the "pop pop" of gunfire and saw people running.

"I really didn't think that's what it was. I thought this can't be happening," she said. "You see your life flash before your eyes."

Josh Maynard, 30, said he and his 20-year-old brother Jerry hit the floor when the well-dressed gunman opened fire. Jerry Maynard said the shooter held his gun sideways and said nothing.

The gunman went to the counter, Miller said, shooting a customer before slowly turning to his left and firing on others before shooting himself.

About 10 to 15 people were believed to be in the restaurant at the time of the shooting, Miller said.

When the shooting stopped, the Maynard brothers ran out of the restaurant. Josh Maynard's blue jeans were torn and his brown leather boots were sliced, damage he said was caused by a bullet that grazed him.

"It felt like somebody kicked me in the foot," he said.

Bob Bertini, a Wendy's Inc. spokesman based in Dublin, Ohio, said the restaurant was cooperating with the sheriff's office.

"This is a terrible and sad day for our restaurant and for this community. It was a senseless tragedy," Bertini said.