As fighters in fatigues lounge in the shade of the rebel camp in the capital of Central African Republic, a boy jumps up to greet visitors with a wide toothy grin. He says he is 14 and joined the rebels three months ago.

It is the wrong thing to say. A female commander in uniform warns him: "We'll kill you if you talk to them."

Her boss, armed with a Kalashnikov rifle, gets up from his plastic chair, stares at the boy who had been playing in the grass moments before and declares: "There are no children here."

Despite the rebel's denial, the United Nations children's agency warns that it has "clear evidence of the continuing recruitment and use of children by armed groups" in Central African Republic.

And an Associated Press reporter saw dozens of youths among the ranks of the Seleka fighters in the capital, Bangui, more than three weeks after the insurgents caused the president to flee the country.

They were riding in pickup trucks with other rebels and in some cases on foot patrol, always closely supervised by older, heavily armed fighters.

Child soldiers were even used in some of the heaviest fighting in the battle for Bangui. They directly engaged troops from South Africa in and around the capital from March 22-24, according to South African soldiers who survived the fighting that left 13 of their comrades dead.

"It was only after the firing had stopped that we saw we had killed kids. We did not come here for this . to kill kids," one paratrooper later told the Sunday Times newspaper in South Africa.

"It makes you sick. They were crying calling for help . calling for (their) moms."

South African Defense Minister Nosiviwe Mapisa-Nqakula said the soldiers from her country had no choice but to shoot back at the children who were firing at them.

"If our soldiers were attacked by children they were correct to defend themselves," she said, according to the South African Press Association. "If a child shoots at you, are you going to ... blow kisses?"

Those who recruit children under the age of 15 to serve in combat can be indicted on war crimes charges, and the International Criminal Court already has convicted one former Congolese warlord of conscripting young fighters.

Soldiers as young as 10 have been used by rebels not only as combatants but also as sex slaves, porters and cooks, according to the U.N.

"Recruiting children is both morally unacceptable and prohibited under international law," said Souleymane Diabate, UNICEF's country representative. "We have called on the new leadership in CAR to ensure that all children associated with armed groups should be released immediately and protected from further violations. "

Even before the latest rebellion launched in December, UNICEF said more than 2,000 children in Central African Republic were with the myriad of armed groups destabilizing the country's north.

The practice is ingrained here in one of the continent's poorest countries. The new Minister of Youth and Sports in Central African Republic comes from a rebel group that has been accused of conscripting child soldiers.

In a country where life expectancy for men is a mere 49 years and many children are put to work at an early age, the rebels in Central African Republic don't view 14 as too young to carry — and shoot — an AK-47 automatic assault rifle.

The government's new information minister, Christophe Gazam Betty, insisted that his government believes only about 40 child soldiers are still with the Seleka fighters.

"If there are combatants who are under the age of 18, there is a system in place through the United Nations," he said. "They will be separated and picked up by UNICEF."

UNICEF says the rebel groups who make up the alliance now in power have previously disarmed child soldiers, and the U.N. children's agency is now calling for that process to start immediately.

Some child soldiers can be returned to their families or to other relatives. Others will be placed in foster homes where possible, though some will be given training on living independently, said Shannon Struthers, UNICEF senior adviser for emergencies.

Many will need counseling and help after actively taking part in combat, Struthers said.