MANASSAS, Va. -- Manassas City police are investigating two robberies from over the weekend.

A 24-year-old man was walking near the intersection of Brent Street and Bartow place on Friday at about 9 p.m. when he was attacked from behind by two men, police said.

One attacker held the victim while the second attacker stabbed him in the abdomen with an unknown sharp object.

The attackers took an undisclosed amount of cash from the victim before fleeing on foot.

On Sunday, a 20-year-old man was attacked near the 7-Eleven store at 8402 Digges Road at about 7 p.m., police said.

The victim was walking to his car when he was knocked to the ground and punched by two men, police said.

The attackers stole the victim's gold necklace and ran off.

The attackers in both cases are described as Hispanic men wearing black or dark hoodies pulled over their heads and jeans.

Anyone with information is asked to call the Crime Solvers tip line at 703-330-0330. Callers may remain anonymous. A reward of up to $1,000 is being offered for information leading to an arrest.