CHANTILLY, Virginia (AP) -- A man wearing military fatigues and throwing punches into the air tried to open the exit door of a jet during a cross-country flight on Tuesday night, airline officials and passengers said.

United Airlines Flight 890 from Los Angeles landed as scheduled at Washington Dulles International Airport at 8:35 p.m., said Amy Kudwa, a Transportation Security Administration spokeswoman. No one was injured.

Ken Wolfenberger, of Whittier, California, who was on the flight, told The Associated Press in a telephone interview that he helped subdue the unruly passenger. The man wore patches on his fatigues with special forces and jujitsu champion logos, Wolfenberger said.

The man had been acting strangely for about 20 minutes, then sat up, wrapped belts around his hands and threw punches into the air, Wolfenberger said.

Wolfenberger said he heard a flight attendant yell for help and tell the man, "Sir, get your hand off the handle."

"Any time you hear a flight attendant shout 'please help,' you worry that something pretty bad is going to happen," he said.

Wolfenberger said the man was held down and punched by other passengers as he grabbed the man's leg. Air marshals then came and took custody of the man.

The passenger became unruly about 31/2 hours into the flight, said United spokeswoman Megan McCarthy.

"After the passenger was restrained, the pilot decided to land at Dulles," McCarthy said. "It wasn't an emergency landing."

Airport police and FBI agents met the flight and were interviewing the passenger, said FBI spokeswoman Debbie Wierman.

There were 138 passengers and six crew members on board, McCarthy said.