But Alexander Ivanko, a United Nations spokesman, said, "Most of the positions located in the south are Bosnian Serb positions."

By dawn, the capital was taking incoming fire, presumably from Bosnian Serb positions.

Colonel Dubois said United Nations troops identified two Bosnian Serb mortar positions and returned 30 rounds of mortar fire at each.

But even though two of them went inside, they said, the others at first took it for a Bosnian Serb position and refused to approach.

We can say that any air strikes on Bosnian Serb positions are ruled out for the simple reason there will be no targets for these strikes.

He compared it to the moment, almost precisely two years ago, when NATO forces began to bomb Bosnian Serb positions.

With crossfire between Bosnian and Serbian positions crackling nearby, the officer radioed for instructions, and was told to leave.

The least bad of these wretched choices would be to announce a series of air strikes on Bosnian Serb positions.

But there appears to be a degree of posturing in this Bosnian position.

Air raid sirens sounded twice today in Banja Luka after officials said Croatian warplanes were flying over Bosnian and Serbian positions about 40 miles away.