Swiss police were still at the scene on Monday (August 31) where a 22-year-old woman was killed and five people injured, one seriously, in a shooting at a rave at the weekend in the Swiss town of Aarau which local police said could have been an act of terrorism.

Local police said all victims are residents of Switzerland and in their 20s. Italy's foreign ministry said Swiss authorities had informed them that an Italian woman had died, and Italy offered its support with the investigation.

A manhunt was underway and large areas of the town were cordoned off, police said, appealing to the public for any images of the incident.

But police admitted that they were at the early stages of the investigation, and that they did not yet know how many attackers there were, nor their motives.

DESCRIPCIÓN DE IMÁGENES

1. POSTER FOR RAVE PARTY AFTER WHICH SHOOTING HAPPENED

2. VARIOUS OF POLICE MINIBUS INSIDE RACING TRACK FIELD WHERE RAVE PARTY TOOK PLACE

3. ROAD LEADING TO RACING TRACK

4. POLICE CAR

5. SIGN FOR RACING TRACK

6. VARIOUS OF POLICE NEAR CRIME SCENE

7. ENTRANCE TO RACE TRACK WITH POLICE CAR

8. TOWN OF AARAU

9. VARIOUS OF MAIN BUS STATION IN AARAU

10. AARGAUER ZEITUNG LOCAL NEWSPAPER AND BLICK NEWSPAPER FRONT PAGES HEADLINING ON SHOOTING

11. AARGAUER ZEITUNG LOCAL NEWSPAPER HEADLINE READING (German): "Deadly attack at Aarau rave party; suspect on the run"

12. BLICK NEWSPAPER HEADLINING ON WOMAN WHO WAS KILLED AT THE RAVE PARTY

13. POLICE NEAR AARAU TRAIN STATION

14. AARE RIVER