Two teenagers have been arrested over the murder of an 11-year-old boy

LONDON (Reuters) - Two teenagers have been arrested over the murder of an 11-year-old boy

shot dead in Liverpool in the latest in a series of youth killings this year and one which Prime Minister Gordon Brown said had shocked the whole country.

Detectives are questioning a boy of 14 and another aged 18 on suspicion of the murder Rhys Jones, who was shot outside the Fir Tree pub in the Croxteth area of the city.

Media reports said the gunman was a hooded youth on a bicycle. Three shots were fired, one of which hit the schoolboy in the neck.

His mother, Melanie, cradled the youngster in the car park after a friend had told her of the shooting.

"The people responsible will be tracked down, arrested and punished," Brown told reporters at Downing Street. He described the killing as "a heinous crime that has shocked the whole of the country".

"Where there is a need for new laws, we will pass them," he added.

Jones, who had been a pupil at Broad Square Primary School, was described as a "lovely boy" by his headteacher Elaine Spencer. She said he was a bright boy who had done well in recent exams.

Merseyside Chief Constable Bernard Hogan-Howe said the boy, who lived nearby with his parents and 17-year-old brother, was an innocent victim.

"This is a sickening incident. In the past we have often come up against a wall of silence but enough is enough and the shooting of an 11-year-old boy demands that the community should come together," he said.

More than 100 officers are investigating the killing. Police sealed off the area around the pub in the area where Manchester United's Wayne Rooney grew up.

Witnesses said the boy, a keen Everton fan, was shot after a youth league football match on Wednesday evening.

"He was just walking out from a game of football at the back of the shop. I don't see why he would have been shot," his friend Joseph White told BBC TV.

Other friends said Jones had never been in trouble.

"He just had a smile on his face every day," one unnamed youngster told the BBC. "He'd get along with anyone. We couldn't say a bad word about him."

Home Secretary Jacqui Smith said she was "desperately sorry" for the boy's family: "It is awful for them, it is awful for the community," she told BBC radio.

The shooting was the latest in a spate of murders of young people across Britain this year that have focused attention on gang-related violence.

Conservative leader David Cameron spoke this week of "anarchy in the UK" and accused Labour of failing to protect communities from crime.