At first, the sticking point seemed to be the width of a 30-mile-long passage linking Serbia with the Serb-held territory in northwestern Bosnia, around Banja Luka.

The towns lie along a corridor that links Serbia to Serb-held territory in Croatia and Bosnia.

They refused to sign, indeed, even though the negotiators had offered a ten-kilometre-wide, UN-controlled corridor linking Serbia to the Serb-held parts of northern Bosnia.

That war, military analysts say, would probably focus on Posavina, where the Serbs must defend a narrow corridor linking Serbia with Serb-held territory in western Bosnia.

It is at the center of a regional market linking Croatia, Serbia and Montenegro and the other countries in the Balkans.

That means taking out the Drina River bridges that link Serbia and Bosnia, and attacking the Croatian entry routes.

Serbian forces have seized much of northern Bosnia to create a corridor linking Serbia to Serbian-occupied areas of western Bosnia and Croatia.

First, it wants control of a corridor across northern Bosnia linking Serbia and Serbian-occupied ares of Croatia.

Bački Breg is in the very northwest of Serbia, on an important highway linking Serbia and Hungary together.