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By Mariam Karouny
BEIRUT, May 15 (Reuters) - Rebel fighters said they were holding U.N. monitors for their own safety in the central Syrian town of Khan Sheikhoun on Tuesday after their car was damaged in what one of the monitors said was an explosion.
The seven-strong team, part of a U.N. monitoring mission overseeing a ceasefire agreement in Syria, was visiting the rebel stronghold at midday (0900 GMT) when violence broke out at a funeral.
Rebels said Syrian forces at a nearby checkpoint fired at the funeral, either with rocket-propelled grenades or from armoured personnel carriers, killing at least 21 people and damaging one of the four U.N. cars.
Syria's Addounya television blamed the violence on gunmen who it said then kidnapped the observers.
The United Nations office in Damascus declined to comment on the incident, but one of the observers in Khan Sheikhoun said none of the team members were hurt and said they were with Free Syrian Army rebels.
"We went to observe and after a while shooting occurred," he told Reuters by telephone, adding the shooting was followed by the blast which damaged the car.
The team was trying to organise a safe return to their base, he said, without giving details.
Internet footage, which activists said was filmed in Khan Sheikhoun on Tuesday, showed a white car of the type used by U.N. monitors with damage to its front which could have been caused by a blast or a collision.
"We are safe with the Free Army and we are waiting for a (U.N.) group to pick us up," a second monitor said.
It was not immediately clear why they were still in Khan Sheikhoun several hours after the violence, when the United Nations has teams in the nearby cities of Hama and Idlib.
Sami al-Kurdi, a spokesman for the rebel military council, said the rebels were working on a safe exit for the observers.
"They are now with the Free Army which is protecting them. If they leave, the regime will terminate them because they have witnessed one of its crimes and it does not want them to tell the truth," he told Reuters.
Another FSA rebel said the observers had been moved to a safer place in the town and were being served food.
(Editing by Janet Lawrence)