The cab driver had stopped his taxicab at Atwells Avenue and Valley Street and was talking with another driver, San Lucas said, when a man approached them for a ride.

When the driver arrived at 62 Fairfield Ave., San Lucas said the passenger put a knife to the driver’s throat and demanded his money.

The driver gave him the $200 in the cab.

“And then the cab driver decides to grab the knife, and he cut his thumb and I guess the assailant fled after that,” San Lucas said.

The police have stopped two suspects who fit the cab drivers’ description of the man, but both were released when it was determined they were not the assailant, San Lucas said.

The Providence Fire Department transported the cab driver to Rhode Island Hospital, Fire Lt. Kevin Gomes said.