Police on Thursday seized the passports of four close family members of wanted war crimes suspect Radovan Karadzic.
His wife, daughter, son-in-law and son — suspected of helping Karadzic to evade capture for more than a decade — were ordered to surrender their passports.
Karadzic, the Bosnian Serb leader during the country's 1992-95 war, is wanted for genocide and other crimes, including the slaughter of up to 8,000 Muslim men and boys in Srebrenica in 1995.
He and his military commander during the war, Ratko Mladic — also charged with genocide — have eluded capture for 11 years.
NATO officials believe the two fugitives are receiving help and money from a network of supporters.
On Thursday, Karadzic's wife, Ljiljana; daughter, Sonja, and her husband, Branislav Jovicevic, handed over their passports and IDs at a police station in the former Bosnian Serb stronghold of Pale, east of Sarajevo.
Karadzic's son, Aleksandar, was home with a broken rib, Sonja Karadzic said, saying they were fulfilling an order to surrender their passports.
No hints on Karadzic's whereabouts
Officials confirmed the order in response to a request from the U.N. war crimes tribunal for the former Yugoslavia in The Hague, Netherlands.
"These four persons are in one way or another the subject of orders by the Court of Bosnia-Herzegovina ... international financial and travel sanctions, and ongoing criminal investigations for their role in the support network of Radovan Karadzic," the office of diplomat Miroslav Lajcak, the international administrator for Bosnia, said in a statement.
"Today's actions build upon these measures," it added.
Mladic is believed to be hiding in Serbia, but there have been no hints about Karadzic's whereabouts for years.
NATO and European Union forces have launched numerous raids on Karadzic's home in Pale as well as those of his children, seizing documents and other materials and questioning family members.
The U.S. government has offered $5 million for information leading to the arrests of Karadzic, Mladic or two other suspects on the run, Stojan Zupljanin, a Bosnian Serb military leader, and Goran Hadzic, a political leader wanted for war crimes in Croatia.