[Migrants, who attempted to flee the Libyan coast to head to Europe, are seen after being detained at the fishing port in the coastal city of Tripoli]By Gabriela Baczynska BRUSSELS (Reuters) - European Union ministers will look on Friday into ways of stemming the flow of migrants who set sail for Europe from Libya and elsewhere in north Africa after a deal with Turkey has cut arrivals via Greece to a trickle. The EU fears the central Mediterranean route to Italy may become the main one now as calmer seas encourage more people to try the perilous journey. The EU is also worried about the long-term impact of massive migration from Africa.