BRUSSELS, Belgium – In a historic move that could extend Europe’s borders to the edge of the volatile Middle East, the European Union recommended yesterday setting mostly Muslim Turkey on a course for full membership in the prosperous 25-nation bloc.

Reflecting widespread misgivings, however, the 30-member E.U. executive commission set tough conditions to prevent Turkey from backtracking on sweeping democratic and human rights reforms.

“This is a qualified yes,” said the european commission president, Romano Prodi. “Our position is a positive one, but also a prudent, cautious one.” President Chirac said talks with Turkey could last 10-15 years “at a minimum.”

Such caution reflected unease throughout a prosperous and mostly Christian continent about union with a poorer Muslim nation that could be a source of unwelcome migrants. Many Europeans recall the old Ottoman Empire, seen as a hostile power that once ruled swaths of Europe to the gates of Vienna, Austria, leaving a legacy of corruption in its wake. It is now up to the E.U.’s 25 leaders to approve the recommendation,paving the way for the start of entry talks as early as next year.

If that happens, as Ankara hopes, Turkey would not actually join the union until around 2015. The commission gave no deadline for a final accession treaty with Turkey.