Police are warning residents of two aggravated carjackings this week in the Greektown and Fulton River District neighborhoods.

In one of the incidents, a valet driver was parking a vehicle when two men approached. The men showed a gun, hit the driver, stole his phone and then stole the vehicle, Chicago Police said.

In the other incident, a person parked their vehicle and was then approached by five men. One of the men showed a gun and then they all got into the vehicle and drove off, police said.

The carjackings happened at 12:04 a.m. Sunday in the 800 block of West Adams Street and at 6:49 p.m. on July 3 in the 700 block of West Fulton Market.

The carjackers were described as men in the 20s or early 30s, police said.

Anyone with informations is asked to contact Area Central detectives (312) 747-8380.