Tuesday's shooting by two teenagers on a suicide mission at Columbine High School, in the Denver suburb of Littleton, left 15 people dead and 23 wounded, police said.

``Children killed children,'' Lucilla Guzman of Colorado's Council of Churches told mourners gathered at an emotional candlelight vigil here Wednesday.

Guzman called on legislators and political leaders to draw up laws banning guns.

``If we don't do this when we have seen this... when children attack children, then it will get worse,'' she said to cheers in the Greek Amphitheater in downtown Denver where some 2,000 mourners gathered.

The shooting has again raised the issue of the ease in which American can obtain weapons and how fatal the consequences can be when they fall into the hands of children.

And it has pushed a debatebetween the powerful US National Rifle Association (NRA) and gun control advocates into news headlines.

The first fallout of the shooting was in the Colorado state legislature, where three gun bills scheduled for consideration were pulled off the table.

The NRA kept a low profile on Wednesday, one week before their scheduled May 1 national membership meeting in -- of all places -- Denver.

Gun advocates had trained their sights on this western city, hoping to weaken local gun control laws and reaffirm the NRA's clout in state houses across the country.

But in a letter to its members late Wednesday, the NRA announced it was modifying its event schedule.

The group was cancelling a gun show along with all other ``festive ceremonies normally associated with our annual gathering,'' the letter read. It was nevertheless going to hold its annual members meeting at the city's convention centre.

The event was modified ``to show our profound sympathy and respect for the families and communities in the Denverarea in their time of great loss,'' according to a letter signed by the current NRA President, actor Charlton Heston.

``Our spirits must endure this terrible suffering together and so must the freedoms that bring us together,'' said the letter. ``We must stand in somber but unshakable unity, even in this time of anguish.''

In Colorado, the shooting came as the state had been considering barring suits against gun makers and making statewide standards for concealed weapons permits. But the legislation has been put on ice.

Fran Allison whose daughter, Brooke, survived the melee at Columbine said: ``I'm violently opposed to the concealed gun bill that (Governor) Bill Owens is about to sign. How can he argue there is a right to bear arms when you look at the tragedy that arms can cause?''

Owens, who visited with the grieving parents, declined to discuss the gun bills, calling such talk ``inappropriate.''

And Denver Mayor Wellington Webb is so opposed to the measure that he published a full-page letter onthe subject in local newspapers last week and sent a recorded phone message to 25,000 people.

The letter cites a 35-percent drop in overall crime and a 42-percent drop in homicides since Denver tightened gun laws five years ago and warns that the proposed bill is a threat to public safety.

On a national level, several gun control laws have been placed before Congress. These include increasing fines for those found selling firearms to minors, and levels fines of up to 10,000 dollars for gun owners whose weapons end up in the hands of a minor.

Desmond Riley, spokesman for the Coalition to Stop Gun Violence, denounced the easy access to guns in the United States.

``There is simply no other consumer product that these kids could have walked to school with an done so much damage with,'' he told AFP.

``To prevent these things in the future we have to do a better job to keep guns out of the hands of young people,'' he added.

According to a recent survey by the gun control lobbying group HandgunControl Inc, 43 percent of US homes with children have a gun.

The Atlanta-based Center for Disease Control reported that 4,463 children and teenagers died of bullet wounds in the United States in 1996, of which 2,836 were murders and 1,309 were suicides.