From The Politically Incorrect Guide to Islam, by Robert Spencer:
"In the 1990's, the Balkans became a favored destination for veterans of the jihad wars in Afghanistan and Chechnya. A prominent jihad commander in Bosnia, Abu Abdel Aziz, explained that he went there after meeting with several Islamic authorities in Saudi Arabia. They "all support," he said, "the religious dictum that 'the fighting in Bosnia is a fight to make the word of Allah supreme and protect the chastity of Muslims.' It is because Allah said (in his holy book), 'Yet, if they as you for succor against religious persecution, it is your duty to give [them] this succor.'...It is then our (religious) duty to defend our Muslim brethren wherever they are, as long as they are persecuted because they are Muslims and not for any other reason."And as for the idea that jihadists are a "minority" of "extremists" bred in the poverty and oppression of the Middle East:
Before, during, and after the 2003 war in Iraq, jihadist streamed into that country from all over the world-including some unexpected places; a German security official noted in late 2003 that "since the end of the war, there has been a large movement of people motivated by Islamic extremism from Germany and the rest of Europe toward Iraq" (Spencer, 128).