By Robin Emmott
BRUSSELS (Reuters) - Belgium has arrested two former detainees of Guantanamo prison on charges of terrorism, saying the men are suspected of seeking recruits to fight in Syria, the federal prosecutor's office said on Friday.
The two men, who were held at the Guantanamo Bay U.S. Naval base in Cuba between 2001 and 2005, were under police surveillance and were arrested in the early hours of Thursday in the Belgian city of Antwerp along with three others.
"They were in a car, we believe waiting to commit a robbery," said Jean-Pascal Thoreau, a spokesman for Belgium's federal prosecutor.
Western fighters in Syria and Iraq have found some of their most willing recruits in Belgium, and per capita Belgium is the European country providing the highest number of citizens to fight with Syrian rebels in recent years, data shows.
Belgium is third only to France and Britain, with nearly 300 citizens traveling to fight between late 2011 and December 2013, according to the International Centre for the Study of Radicalisation.
The two men accused are Moussa Zemmouri, a 37-year-old Belgian of Moroccan origin, and an Algerian whom the prosecutor's office identified as Soufiane A and who is suspected of spending time in Syria.
Zemmouri was captured in the Kandahar region in southern Afghanistan following the Sept. 11, 2001 attacks. He was flown back to Belgium in April 2005 and later released after spending time in a Belgian prison.
Guantanamo was set up after the Sept. 11 attacks for al Qaeda and Taliban detainees. Obama vowed to close it within a year when he came to office in 2009. The White House said on Wednesday it was in the final stage of drafting a plan for closing the prison for foreign terrorism suspects.
(Reporting by Robin Emmott)