BANGKOK (AFP) – Thai anti-government protesters have set the offices of TV station Channel 3 on fire, trapping 100 staff in the building, a fire department official said Wednesday.

Military officials told AFP they had sent a helicopter to begin an airlift and were looking at the building plans to see where they could land the chopper.

''The building was attacked by the protesters and when we dispatched a fire truck it was also attacked. Now they have withdrawn so we have sent a fire truck again,'' a spokesman for the Bangkok fire department told AFP.

Channel 3 managers said the staff were trapped above a fire blazing on the sixth floor of the building, which is located on a main thoroughfare that leads to the Red Shirts' protest camp, which was stormed by troops earlier Wednesday.

''We are in a crisis situation now. Some 100 of our staff are trapped inside, the fire has engulfed the sixth floor,'' Channel 3 news editor Samran Chatto told AFP.

Earlier, Thailand’s anti-government “Red Shirts” on Wednesday ended their street protest campaign as leaders surrendered to police after a military offensive against their rally base.

At least seven Red Shirts leaders turned themselves in, after an overwhelming operation by troops who punched through the barricades of their camp in Bangkok's shopping district which they have occupied for six weeks.

At least five people were killed when armed troops smashed down barricades and clashed with demonstrators.

After troops smashed the camp of the Red Shirts, their leaders asked thousands of supporters to leave, and to proceed to an area where the government has laid on buses so they can depart the capital.

''I ask everyone to go home,'' said senior Reds figure Nattawut Saikuar in a television interview from the National Police Office where he was in custody.

''There will be police guarding the road and providing security for you. I hope that you return home safely,'' he said.

Earlier, Reds leaders had tearfully announced the end of their protest movement in front of a large crowd of emotional supporters, including many women and children.

''I know that you are suffering. Some of us are speechless. But we want to stop any more deaths here,'' said Jatuporn Prompan.

''I know that if the military comes here many of you will sacrifice your lives and we cannot stand to see that.''

''We are ending the protests here,'' said Nattawut from the main protest stage. ''I know this is unacceptable to some of you and some of you do not want to hear but we cannot stand against this cruelty.''

''We will exchange our freedom with your safety. We have tried our best.''