Armed gangs continued to show their contempt for the law this weekend by carrying out a series of gun attacks - one fatal - across England.

A man was killed in east London as armedpolice patrolled the southern boroughsofthecitywherethree teenagers have been shot dead in the past week. Three others were hurt in two incidentsinManchesteronFriday.

The latest murder took place in the early hours of yesterday morning in Hackney, east London. Gunmen shot a 28-year-old man in his car before firing at him again as he tried to escape.

A witness reported seeing three black men walking "confidently" away from their victim as he lay dying.

Gabriel Ajayi, 50, whose flat overlooks the scene, was woken by three gunshots shortly before 5.30am. He said: "I looked out and saw a man lying on the ground on the road and I saw three guys running away. All of a sudden they came back and shot him twice again at close range."

The man was rushed to hospital but pronounced dead just before 6am.

The incident is being investigated by detectives from Operation Trident, the Metropolitan Police's black-on-black gun crime unit. Police said the latest shooting was not being linked to the earlier murders in south London.

In Manchester's Moss Side, an 18-year-old man was shot in the back on Friday night while standing with friends outside a youth club. Later that night two men, aged 19 and 27, were shot as they sat in their car at traffic lights elsewhere in the city. Their injuries are not believed to be life-threatening.

Chief Superintendent Dave Keller, of Greater Manchester Police, said overall gun crime in the city had been falling, although there has been a rise in recent months. He said: "Clearly there are tensions in the area. This problem is caused by a small number of individuals. We are actively targeting those individuals."

Police are open to the suggestion that the Manchester shootings may have been inspired in part by the shootings of three youths in south London.

This weekend, extra armed police were on the streets of the UK capital, as Scotland Yard's Operation Neon focused on the south London boroughs of Lambeth and Southwark. Meanwhile, home secretary John Reid announced he is to consider introducing tougher sentences to tackle gun crime and gang culture.

Tony Blair described the deaths of the three teenagers in south London as "horrific, shocking and tragic beyond belief".

Scotland Yard said three people were arrested overnight on Friday during searches of suspicious vehicles, although none was linked to the shootings.