Former President Jimmy Carter brings his free-lance peace efforts to the former Yugoslavia on Sunday, despite widespread skepticism that he can help end the 32-month-old Bosnian conflict.

There were unconfirmed reports that a key government-held town in northwestern Bosnia had fallen.Carter left Atlanta Saturday on a plane for Germany. He said he would go to Zagreb, Croatia, headquarters of the U.N. mission to former Yugoslavia, and decide then whether to travel to Sarajevo.

A statement from the Carter Center in Atlanta said Carter decided to make the trip after "extensive discussions" with the White House and U.N. officials. He planned to leave Saturday.

Carter said he would meet with Croatian President Franjo Tudj-man and Bosnian Prime Minister Haris Silajdzic in Zagreb. He also was expected to meet with the U.N. chief for former Yugoslavia, Yasushi Akashi of Japan.

If he decides to go to Bosnia, Carter was expected to visit Bosnian Serb headquarters at Pale, outside Sarajevo, and Belgrade, the capital of Serbia.

Bosnian Serb leader Radovan Karadzic invited Carter to help restart peace talks. Carter successfully intervened this year to break deadlocks and resolve crises in Haiti and North Korea.

But the visit is raising concern from all sides that Karadzic is using Carter to undermine an international peace plan that would reduce Serb territory in Bosnia to 49 percent from the 70 percent it now holds.

White House Chief of Staff Leon Panetta, speaking on CNN's "Evans and Novak," questioned Carter's ability to resolve Bosnian issues "because they are very complicated and because we have seen that, frankly, the motives . . . involved here with the parties are always suspect."

The visit has also been questioned by Bosnian leaders, Serbia's powerful leader Slobodan Mi-lo-se-vic, and Russia, a traditional Serbian ally.

Carter said he will encourage the Bosnian Serbs to accept the peace plan.

"My purpose in traveling to the region is to seek ways to contribute to the cessation of hostilities and to encourage the acceptance of the contact group's plan as the basis for negotiations," he said.

To lure Carter to Bosnia, Karadzic pledged Wednesday to ease tension with the United Nations that increased following three NATO airstrikes on Serb targets. Hundreds of peacekeepers were detained and U.N. movements through Serb-controlled territory were virtually frozen.

The Serbs allowed two U.N. flights to land Saturday at Sarajevo's airport, which had been closed since Nov. 21 after Serbs positioned anti-aircraft missiles nearby. Sources said one plane carried an advance team for Carter.