A US worker who had recently tried to convert colleagues to Islam beheaded one of them with a knife after being fired from his job at a food distributor, police said Friday.

The incident happened Thursday at a food business in Oklahoma where the suspect, identified as 30-year-old Alton Nolen, went on a rampage after being told he had been sacked.

"Nolen went to the parking lot, then drove his vehicle to the front of the business ... Nolen then entered the main entrance into the front office," said police spokesman Jeremy Lewis in the city of Moore.

"Nolen encountered and killed Colleen Hufford with a knife. During the attack, Nolen severed the victim's head," he said in a statement.

The suspect then attacked another colleague with a knife, before being shot by the firm's chief operating officer.

Both the second knife victim and the alleged attacker were taken to hospital where they were in stable condition.

"After conducting interviews with Nolen's co-workers, information was obtained that he recently started trying to convert several employees to the Muslim religion," said the police spokesman.

Because of the nature of the crime local police called in the Federal Bureau of Investigations (FBI), he said.

The incident comes after a series of beheadings of western captives by militants in Syria and Algeria, posing in online videos, but US officials have not confirmed any link to the Oklahoma case.