Four people were killed and 15 people injured Saturday night in two separate shootings in the United States, police said Sunday.

The first incident took place in Portland, Ore., where a gunman killed two teenage girls and injured seven others outside an underage nightclub before shooting himself in the head, Rosie Sizer, the city's police chief told reporters.

Sizer described the shooting as "unprecedented" in Portland.

The shooter was identified only as a 24-year-old man who was in critical condition in hospital on Sunday.

One of the wounded victims was also in critical condition, four in stable condition and the rest two had been released.

There was no indication that the suspect knew the victims.

In the second case, two people died and seven were wounded in a shooting in Wichita, Kan.

Of the injured, one was in critical condition at a Wichita hospital, and four were listed as serious.

The city's deputy police chief Robert Lee said the shooting took place during a wake at a home.

"During the wake, persons arrived and fired," Lee said, but he could not specify how many gunmen there were.

Lee said police will be investigating throughout the weekend.

(Xinhua News Agency January 26, 2009)