STONY BROOK - Stony Brook University has stepped up security following an armed robbery and an attempted robbery on the campus.

On Sunday, authorities say two or three men approached a young man walking alone. They say one man pulled out a knife and demanded that the victim hand over his phone and wallet.

Then, on Tuesday, police say two masked men approached two students with what is believed to be an Airsoft pistol and demanded money. The pair claimed they didn't have any money on them, so police say the would-be crooks took off.

Both times, police say the victims were walking on a bicycle path near the athletic fields after dark. In both incidents, authorities say the suspects then calmly headed to the Long Island Rail Road parking lot. They say it's not clear if the suspects stayed on campus, jumped in a car, hopped on a train or went down a path that leads off campus and onto Route 25A.