WASHINGTON, D.C.: Concerned about the progress of the peace, Secretary of State Warren Christopher traveled to Bosnia Friday on the eve of a crucial deadline. This is the weekend, reports TIME's Edward Barnes, when all Bosnian Serb forces are supposed to withdraw from the suburbs of Sarajevo. "Christopher will be asked to extend the deadline and the question will be whether he caves in or not," says Barnes. "So far the effort to forestall the destruction of the suburbs is failing. There has been an exodus of many of the Serbs. Houses have been burnt as they leave. Many of the factories have been dismantled. The only police there now are special police who work for Bosnian Serb leader Radovan Karadzic, and they are very bitter. The question is whether they will leave anything standing when they go." Once again, says Barnes, Sarajevo is a flashpoint for the Balkans. "And right now the situation there looks dire. The United Nations has failed miserably to get a police force in and NATO has not taken up the slack. Sniper incidents are on the rise again. An American was wounded by one earlier this week and yesterday French troops killed a sniper. It's a problem of major proportions." Christopher plans to meet with all the Balkan leaders: Serbian President Slobodan Milosevic, Croatian President Franco Tudjman and Bosnian President Alija Izetbegovic.