In a day that began with exuberance and ended in accusations, the Sarajevo suburb of Ilidza was handed over to the Muslim-Croat federation.

Abandoned by Serbs who feared living with their former foes, Ilidza was the fourth of five Serb-held areas of Sarajevo to be transferred.But Tuesday's handover did not go smoothly: Serbs were blamed for arson fires that gutted homes, factories and warehouses, and Bosnian gangs for looting and harassing the few remaining Serb residents.

Earlier in the day, thousands of honking cars and Sarajevo taxis clogged the streets of this southwestern suburb. Hundreds clapped and cheered as the police fixed a sign on city hall proclaiming it federation territory.

Some old friends and neighbors were reunited for the first time in years.

Slavko Dumancic, an 80-year-old Serb, and Suljo Zajragic, a 68-year-old Muslim, hugged and cried after they ran into each other in the crowd.

"The last four years were hell, especially the last four days," Dumancic said, tears rolling down his cheeks. "But the most important thing is that it is over now and that friends are together again."

But after the formal ceremonies ended, international organizations were "swamped" with reports of people being threatened and harassed and property being stolen, said U.N. aid agency spokesman Kris Janowski. Many people came "to steal and loot," he said.

Federation and international police were doing their best but could not respond to all calls, he said. "It's a very bad situation."

Martin Moylan, of the international police in Ilidza, said there were "numerous reports of people threatened to leave the area."

International police received reports of cars stolen, houses looted, a man and a woman attacked in separate instances. Adil Muja-novic, a federal police official, blamed "Bosnian thugs."

One house was burning Tuesday night, apparently set ablaze by a departing family. A warehouse was also on fire.

In Grbavica, the last Serb-held neighborhood to be transferred to federation control on March 19, looting and arson also continued.

The NATO-led peace force and unarmed international police increased patrols there in an attempt to prevent the lawlessness that marked the handover of the other four suburbs.

The NATO commander in Bosnia, Adm. Leighton Smith, blasted the Bosnian Serb leadership for encouraging the Serb exodus.

"They were clearly doing the kinds of things that were instilling absolute, utter, total fear into the people," he said, singling out Bosnian Serb leader Radovan Karadzic as "the worst of the bunch . . . talking about his ethnically pure `greater Serbia.' "