COPENHAGEN, Jan 17 (Reuters) - Denmark said on Tuesday the Seychelles had refused to take 25 suspected Somali pirates detained by one of its warships earlier this month, highlighting the difficulty of putting pirates on trial.
The pirates remain aboard the Danish warship Absalon which captured them and their fishing vessel on Jan. 7.
Denmark had sought to send them to the Seychelles under a May 2011 agreement that was supposed to allow the Danish navy to hand over suspected pirates for prosecution in the Indian Ocean island country.
Prime Minister Helle Thorning-Schmidt said Danish diplomats were working to find an alternative to the Seychelles, which lie about 1,600 kilometres (990 miles) off the east coast of Africa, to try the pirates in the region.
"It's not a good situation obviously," Thorning-Schmidt said. "Now we just need the extradition agreements."
A Danish government official said last May's agreement did not oblige the Seychelles to take pirates, but only to consider on a case-by-case basis whether its judicial system had the capacity to handle the cases.
Many suspected pirates arrested off the Horn of Africa are released after only a short detention because governments are reluctant to bring them to trial and prison facilities in Somalia are inadequate.
Danish Foreign Ministry officials declined to say which countries Copenhagen has asked to try the pirates, but Denmark last year sent 24 pirates to Kenya for trial.
Thomas Winkler, Denmark's top legal official dealing with piracy, told Reuters the main challenge was to find prisons where convicted pirates could serve their sentences.
"If we get the incarceration part in Somalia up and running, a number of states have said they are willing to increase the prosecution (of pirates)," he said.
"So the key bottleneck right now is the prison facilities and systems in Puntiland and Somaliland," Winkler added.
Winkler, who also heads the legal committee of the U.N. Contact Group on Piracy off the Coast of Somalia, said the first full-fledged piracy prisons would be ready some time in 2013.
Experts say that about 90 percent of captured pirates are being turned lose because there is no place to prosecute them.
Western governments generally do not want to take them from the region to their own courts, though France in November began the first of four trials of Somali pirates in French courts. (Reporting by John Acher; additional reporting by Henriette Jacobsen; Editing by Jon Boyle)