Dutch police have arrested two Syrian nationals suspected of trafficking thousands of people into Europe, AFP reports.

Workers in Hungary are laying down more temporary border fencing, this time on its border with Croatia. Earlier this week it completed a temporary fence along the border with Serbia. It has also begun arresting undocumented immigrants.

Image source, EPA

For the latest from our team of correspondents across Europe covering the migrant crisis, follow our twitter list, external. 

Image source, AP

A record 473,887 refugees and migrants have crossed the Mediterranean into Europe so far in 2015, the International Organization for Migration (IOM) says. The number includes at least 182,000 Syrians - almost 40% of the total. The figure also represents a rise of almost 9,000 from the IOM total given earlier this week.

BBC correspondent Christian Fraser, who is on the border between Slovenia and Croatia, says a helicopter is now hovering overhead. He watched earlier as a group of 30 migrants crossed from Croatia into Slovenia unchecked. He says the area is surrounded by fields and that the border looks "very porous". 

Libyan authorities have arrested more than 100 people near Tripoli as they were preparing to cross the Mediterranean to Europe, an official has told the AFP news agency. He said 124 migrants, including eight women, were stopped in Qarabulli as they prepared to head to a boat bound for Europe.

Croatian Prime Minister Milanovic calls for an urgent meeting of his country's National Security Council to discuss further steps in dealing with the migrant crisis. He says Croatia will "provide migrants with food, water and medical help, where necessary" but cannot continue to take in more migrants.

The Croatian Prime Minister, Zoran Milanovic, is giving a news conference. He says building fences is not a "solution", and neither is closing borders. But he urges European leaders to realise Croatia cannot be a "hotspot" or house "hundreds of thousands" of migrants, from which other countries will pick and choose individual migrants they want.

The BBC's Simon Smith says crowds are gathering at Beli Manastir station in eastern Croatia. A local fire engine has now arrived and firefighters have turned water taps on to allow people to wash and drink from.

Here's a useful map showing why people are so desperate to move through Croatia into neighbouring countries.

It's all to do with the Schengen Agreement, which abolished the EU's internal borders and is explained here.