The Latest: Central Europe states create Friends of Schengen

The prime ministers of four central European countries say they want to preserve the European visa-free Schengen zone that is threatened by the current wave of migrants.

The United Nations refugee agency says it's "deeply concerned" about the violence at the border between Greece and Macedonia where scuffles have broken out between different migrant groups.

Greek authorities say they have recovered the body of a woman and are still searching for three other missing migrants after their small boat sank in the eastern Aegean Sea.

The boat was carrying a total of seven migrants, and the coast guard says three survivors were pulled from the sea after Thursday's capsizing off the island of Farmakonissi.

Greece is at the forefront of Europe's immigration crisis, with more than 700,000 people having crossed over so far this year from nearby Turkey, in rickety boats provided by smuggling gangs charging high fees.

Greece is at the forefront of Europe's immigration crisis, with more than 700,000 people having crossed over so far this year from nearby Turkey, in frail boats provided by smuggling gangs charging high fees.

Pressure is mounting on Greece to ensure better control of its borders and register arriving migrants or face the prospect that passport checks could be reintroduced for Greek citizens in Europe.

The European Union urged Greece on Thursday to step up controls on its sea and land borders, and EU interior ministers will discuss on Friday the state of border controls in the country.

British authorities say a Palestinian man suspected to be the leader of an organized criminal gang that smuggled thousands of migrants into Europe faces extradition to Greece.

Authorities say the gang, based in Greece, is believed to have earned nearly 10 million euros ($ 10.6 million) since 2013 by charging migrants for transportation, forged documents and housing.

Serbia's prime minister has urged a joint international effo