BALKANS: A decade after hundreds of Arab fighters arrived in Bosnia to help local Muslims fight Serb and Croat forces, al-Qaeda may be building a Balkan launch pad for attacks on US allies in the region and targets in western Europe.
So say many security experts and US officials, who are urging governments and peacekeeping forces in the region to focus more money and effort on neutralising what they call a growing terror threat on Europe's south-east flank.
The chief of Bulgaria's secret service, Gen Kircho Kirov, this week became the latest senior official to warn of mounting danger to countries like Poland, Hungary, Romania and Bulgaria itself, whose deployment of troops to serve alongside US forces in Iraq have made them potential targets for attack by Islamic extremists.
"We have information that people with connections to structures linked to al-Qaeda have passed through Bulgaria on their way to neighbouring or other European countries," Gen Kirov said.
"There are people in the Balkans who have been in Chechnya and Afghanistan. Some have been active in Iraq. The movement of these people is not random and has to be monitored," he cautioned, adding that Bulgaria was sometimes used "as a logistics base for terrorist structures".
Gen Kirov is only the latest to sound a warning over the attractiveness of the Balkans for groups looking to establish a base as close as possible to intended targets.
Mr Yossef Bodansky, director of the Task Force on Terrorism and Unconventional Warfare in the US Congress, recently said: "There is a terrorist network in Bosnia, composed of several well-trained and connected groups, which are directly or indirectly responsible to . . . Osama Bin Laden."
He claimed that men trained in Bosnia took part in suicide attacks in Baghdad last August, including the bombing of UN headquarters which killed 22 people.
"Representatives of the international community in Bosnia and [ local] authorities are aware of this but they do not work enough to fight international terrorism."
Mr Bodansky and others say Bosnia has played a key role in boosting the international dimension of radical Islam.
Foreign mujahedeen descended on the country in the early 1990s, after the withdrawal of Soviet troops from Afghanistan left them looking for a new enemy and just as Bosnia's Muslims became embroiled in bitter fighting with Serb and Croat forces.
Many of them stayed on after the conflict, married local women and took Bosnian passports; more than 700 foreign fighters are known to have been illegally granted Bosnian citizenship after the 1992-95 war, which killed some 250,000 people.
In testimony last May to the US commission investigating the attacks of September 11th, 2001, outgoing CIA chief Mr George Tenet said the fighters who left Bosnia after the war provided "a ready supply of manpower for terrorist operations".
Security analysts say they fanned out in varying numbers to fight for causes in Chechnya, Kashmir, back in Afghanistan and now Iraq, while others stayed in Bosnia, perhaps in "sleeper cells" which await the order to attack somewhere in Europe.
Bosnian war veterans have been implicated in the kidnapping and execution of US citizens in Iraq and the Madrid train bombing which killed 191 people last March.
Large and disaffected Albanian Muslim communities in Kosovo and Macedonia could also offer a fertile ground to radical Islam, some commentators warn.
While recognising the need for vigilance, however, many people say Balkan countries may be tempted to exaggerate the terror threat in the hope of attracting US funds and - in the case of Bulgaria - perhaps even a US military base.
Others analysts warn that the increasing - and unwarranted - US focus on al-Qaeda could compromise vital efforts to catch war crimes suspects and fight rampant organised crime. "The US intelligence people are concentrating on suspected Islamists and not on known war criminals," Mr Senad Slatina of the International Crisis Group in Sarajevo said. "It is effectively becoming a witch hunt."