The European Union has lost control of its borders and risks total collapse if they are not sealed, a senior Brussels diplomat has warned.Donald Tusk, president of the European Council, warned the EU was now facing a "critical point" and that the migrant crisis hadn't even reached its peak. As he chaired an emergency meeting of EU leaders in Brussels last night Mr Tusk painted a bleak picture of the EU's future, saying the 28-member bloc was on the verge of breakdown with "recriminations and misunderstanding" pitting nations against one another. The future of free movement was at stake, he said, as the continent had lost control of its borders as well as a "sense of order".He added: "The most urgent question we should ask ourselves...is how to regain control of our external borders. "Otherwise, it doesn't make sense to even speak about common migration policy." He appeared to lay much of the blame with Germany, accusing Chancellor Angela Merkel of exacerbating the problem by sending the signal to desperate Syrians fleeing their war-torn homeland that Germany had no limit on the number of migrants it would accept.He added: "We need to correct our policy of open doors and windows. "Today we are talking about millions of potential refugees trying to reach Europe, not thousands. "It is likely that more refugees will flow towards Europe, not less. Especially as almost all of them feel invited to Europe."But Ms Merkel responded: "Setting up fences between members states is not the solution. "Faced with a great challenge, it can not be that Europe says we can't handle this. "That's why I say again and again, we can do this." As deep divisions continue to show between EU nations, French President Francois Hollande offered a stark assessment of the crisis engulfing the continent. He said: "Those who don't share our values, those who don't even want to respect those principles, need to start asking themselves questions about their place in the European Union."More than half a million migrants have arrived in Europe so far this year, and experts believe the total figure for 2015 could top one million. David Cameron, who was also attending the Brussels summit, has pledged an additional £100m in aid for camps bordering Syria, from which Britain will offer 20,000 refugees asylum over the next four years. £40m of that sum will go to support the UN's World food Programme.Mr Cameron said: "We must make sure that people in refugee camps are properly fed and looked after, not least to help them but also to stop people wanting to make, or thinking of making this very, very difficult and very dangerous journey to Europe." EU leaders have pledged €1billion (£734m) to help countries bordering the war zone in a bid to stop refugees from wanting to make the journey to Europe in the first place.