A gunman killed five people and injured several others in a shopping mall in Salt Lake City last night - apparently shooting at random - before he was killed. Witnesses at Trolley Square mall, which is south-east of the centre of Utah`s state capital, said they heard about 20 shots being fired and saw a man in a trench coat with a shotgun or rifle exchanging fire with police officers. One witness said he saw police shoot the gunman, who had entered the vast two-storey mall at around 6.45pm local time (0145 GMT). Authorities have released few details about the incident, however Detective Robin Snyder said: "We have six fatalities and multiple victims at hospitals. They were found throughout the mall. I don`t know male or female or ages." The mall was busy with shoppers when the shootings started; survivors later described how they hid in storerooms and bathrooms after hearing shots. Among the injured, three people were in a critical condition and a fourth was in a serious condition. Two of the critically injured were a 16-year-old man and a 50-year-old man. An off-duty police officer was in the mall - a sprawling complex with 80 shops and restaurants - police said. The officer was involved in the shooting but was not injured. Barrett Dodds, 29, an antique store owner, said he saw a man exchanging gunfire with a police officer outside a card store. The gunman, he said, then backed into a children`s clothing store. "I saw the cops go in the store. I saw the shooter go down," said Mr Dodds, who watched from the second floor. Barb McKeown, 60, of Washington DC, was in another antique shop when two women ran in and reported gunshots. "Then we heard shot after shot after shot - loud, loud, loud," said Ms McKeown, saying she heard about 20. She and three other people hid under a staircase until it was safe to leave. Matt Lund, whose wife manages a clothing store, said he saw a woman`s body face down at the entrance to one store, Pottery Barn Kids. He locked himself and four others inside a storage room for about 40 minutes and said he heard the violence outside. "We heard them say, `Police! Drop your weapon!` Then we heard shotgun fire. Then there was a barrage of gunfire," Mr Lund, 44, said. "It was hard to believe." Marie Smith, 23, had the day off from Bath & Body Works but stopped there during an errand and saw the gunman shoot a woman in front of the store. "He was ahead of her, standing still. I don`t think she saw that he had a gun," said Ms Smith, who rushed to a bathroom and locked herself in. Police spent several hours after the shooting searching stores at the mall for shoppers and employees who were in hiding. The mall is a refurbished trolley barn built in 1908, with a series of winding hallways, brick floors, wrought-iron balconies. Last night outside the mall, streets were blocked by police activity. Dozens of people lingered on the pavement, many wrapped in blankets, as they talked about what they had seen inside. - Associated Press