Authorities say an MTA bus driver suffered a medical emergency moments before he lost control of a bus and plowed into more than a dozen parked vehicles in Brooklyn Friday evening, injuring several people.

The FDNY says the B48 bus slammed into the cars along Nassau Avenue in Greenpoint at about 7:30 p.m. About 15 cars in all were hit, including a pickup truck crossing at Kingsland Avenue.

"There was no screeching brakes," said Steve Eccardi, whose wife's car was damaged in the accident. "It was ripping of metal all the way down the block."

A nearby pizza store worker described the efforts to rescue passengers on the bus once it finally came to a stop near Sutton Street.

"A guy started kicking in the bus doors. They got everyone off, everyone seemed fine. But the bus driver was passed out to the side," said Henrik Toncic.

"I heard a bunch of people running and screaming," said Eccardi.

Six people, including the driver of the bus, were hurt and taken to Woodhull Hospital, authorities say.

"I'm hoping the bus driver is OK," said Sandy Reilly, whose car was damaged in the crash.