The United States Government has offered a reward of up to $5m for the capture of a Croatian general accused of war crimes.
Gotovina: Accused of the murder and disappearance of hundreds of Serbs
Ante Gotovina is the Hague tribunal's third most wanted man.
News of the reward came as Croatian Prime Minister Ivica Racan held talks in Brussels about his country's bid for European Union membership.
Croatia's chances of joining the EU could depend on its willingness to hunt for Mr Gotovina and hand him over.
In a visit to Zagreb last week the tribunal's chief prosecutor, Carla del Ponte, urged Mr Gotovina to surrender.
Ms del Ponte says she believes he is still in Croatia but the government says he has probably fled the country.
She is due to report to the UN Security Council later on Thursday on the co-operation by former Yugoslav republics with the tribunal.
The EU has said it will attach great significance to the report.
'Ready to help'
The US reward is part of the State Department's Rewards for Justice programme, which is also offering money for the first two on the UN list, Bosnian Serb wartime leaders Radovan Karadzic and Ratko Mladic.
The reward was announced by Pierre-Richard Prosper, US ambassador at large for war crimes issues, in the Zagreb daily Jutarnji List on Thursday.
"We are ready to help the Croatian Government to arrest Gotovina by offering a reward ... to anyone who furnishes information on where he is located," he said.
Del Ponte believes Gotovina is in Croatia
Mr Prosper added that Washington had information that he was hiding in Croatia under the protection of a network of people, some of whom were involved in criminal activity.
Mr Gotovina is accused of arranging the killing of at least 150 Serb civilians and the expulsion of 150,000 others following a government operation in 1995 to recapture territory held by rebels.
Croatia has said it will hand him over without hesitation if he is found.
But correspondents say the government knows Mr Gotovina's arrest would be deeply unpopular with many Croats.
Mr Racan is hoping to persuade European officials that Croatia is fit to join the EU in 2007 along with Romania and Bulgaria.
set itself a number of tasks that it wishes to fulfill," he said after meeting EU foreign policy chief Javier Solana.
Meanwhile Mr Solana praised Mr Racan's efforts to "move his country closer to the EU".
The European Commission is due to rule early next year on whether to include Croatia as an official candidate country.
The United Kingdom and the Netherlands have already said they will not ratify the first stage of the process until Mr Gotovina is handed over.