Ten kayakers were rescued after five of them were injured in a collision with a ferry on the Hudson River near West 39th Street on Tuesday, the authorities said.

The kayakers, nine clients of Manhattan Kayak Company and one of the company’s employees, were headed south on the river when the collision occurred, Inspector David Driscoll, the commander of the New York Police Department’s Harbor Unit, said at a news conference on Tuesday night. At least two of the kayaks were struck by a NY Waterway ferry, the police said.

The employee, whose name was not released, sustained the most serious injuries, with one arm appearing to be partially severed, Inspector Driscoll said. The inspector said the employee had lost “a lot of blood” and “was lapsing in and out of consciousness.” Officer Tommy Le of the Harbor Unit said he had applied a tourniquet to the man’s arm.

Two men and two women sustained minor injuries in the collision, including cuts to the head and injuries to their backs and shoulders, the authorities said.