YUGOSLAVIA-BELGRADE:21APR99 - A fire burns out of control in a building in Belgrade April 21. A NATO air attack on Belgrade hit the headquarters of Yugoslav President Slobodan Milosevic's Socialist Party on Wednesday, and witnesses said at least 15 civilians were trapped in the building. Witnesses said three missiles were fired at the building at 3:15 a.m. (0115 GMT), of which at least one hit the target.

EV/WS