Albright Condemns ‘Murderous’ Shelling of Sarajevo : Balkans: U.S. envoy to U.N. warns Serbia of continued sanctions and issues a caution to Croatia.

Madeleine Albright, the U.S. ambassador to the United Nations, on Friday condemned the “murderous bombardment” of Sarajevo by Bosnian Serbs and put all combatants on notice that blocking aid will be considered a war crime.

As she wrapped up the highest-level American visit to the former Yugoslavia since war broke out in 1991, Albright repeated warnings that stiff U.N. sanctions against Serbia will continue as long as Serbian rebels imperil Bosnian civilians, and she confirmed that an embargo has also been threatened against Croatia if it worsens Bosnia’s suffering.

The message sent by Albright’s three-day tour of Croatia was one of staunch American support for humanitarian work in the ravaged Balkans and an intention to see justice brought to those responsible for atrocities.

“We put all parties on notice that the United States firmly believes that preventing or hindering the delivery of humanitarian aid in this conflict should be investigated by the prosecutor for war crimes,” Albright told reporters as she prepared to leave for Poland.

“The United States will not support the easing or the lifting of sanctions by the Security Council if, for example, Serbian elements obstruct that work, nor will the United States recognize any amnesty for war criminals,” she said.

A day earlier, Albright visited the scene of a mass grave in Serb-occupied eastern Croatia, in the village of Ovcara, where at least 200 Croats are believed to be buried.

Asked if she discussed sanctions against Croatia in her meeting with Croatian President Franjo Tudjman, the U.N. envoy said she had. She said she insisted that he use his influence with Bosnian Croat nationalists to ensure that they comply with cease-fire and safe-passage accords they have signed.

Tudjman “is very much aware of the concern of the United States about actions of the HVO,” Albright said, referring to the Bosnian Croat army.

The Security Council imposed sanctions on the Serb-ruled remains of the Yugoslav federation in May, 1992, in punishment of Belgrade’s arming and instigating of Serb rebels who encircled Sarajevo with artillery and have been laying siege to the capital for 21 months.

Bosnian Croats turned against their former Muslim allies in the defense against the Serbian siege more than a year ago, aided by heavy artillery and troops sent by Zagreb.

The international community has repeatedly raised the prospect of sanctions against Croatia but appears fearful of strengthening the hand of nationalist extremists, as has happened in Serbia.

While Albright made a point of noting all parties have thwarted life-saving relief work, she singled out Serbs for particular criticism more than once.

“We need evidence that the Bosnian Serbs are using all of their influence to guarantee free passage” for relief convoys, she said in an interview with Croatian television.

Taking note of the intensified shelling of Sarajevo this week, in which at least 40 civilians have been killed, Albright said she favors tightening sanctions on Belgrade as long as the Serbs persist with their aggressive actions.

U.S. policy in Bosnia has become a major issue ahead of a summit of the 16-nation North Atlantic Treaty Organization next week, especially after appeals by France for more direct military involvement of U.S. troops in Bosnia.