UPDATE: The driver of the bus, Scott William Chase, 46, was arrested by SWAT team members about 4:50 p.m. Chase, who has no known address and is listed as a transient, is being evaluated by mental health professionals and could be be charged with criminal mischief and disorderly conduct. The investigation is ongoing.

A man driving an old school bus who claimed he was going to be "extracted" by a jet aircraft drove the bus onto the one operational runway at the Baker City Airport this morning and then refused to leave, leading police to close the airport about three miles northeast of the city.

The man has a beard and looked to be in his mid 40s to early 50s, said Dustin Stephens, the chief pilot for Baker Aircraft, the fixed base operator at the city-owned airport.

Stephens said he was on the phone in an airport office about 8:30 a.m. when the bus arrived and drove out to the taxiway beside the runway, an area open to aircraft only. Stephens said he and two other employees drove out to talk to the bus driver, who rolled down the window and "started screaming at us," Stephens said.

He said the man told them a "big jet" was coming to pick him up, and that the plane would also haul away his bus. The man claimed he had "nuclear" material in the bus.

Stephens said the man apparently had been found trespassing in the Halfway area recently. Stephens said it appeared the man was alone.

Officers from the Sheriff's office and the Baker City Police are at the airport. which is about 3 miles northeast of the city. Public access to the airport is blocked at the intersection of the frontage road on the east side of Interstate 84 and South Airport Lane.

Stephens said traffic at the airport varies, but typically on a January day between 3 and 10 planes would land, in most cases to buy fuel.