European Union leaders are holding an emergency summit Monday with Turkey aimed at staunching the flow of migrants to Europe as they search for a solution to the continent's worst refugee crisis since World War II.
About 134,000 migrants have crossed the Mediterranean Sea to Europe so far this year, the International Organization for Migration said, with more than 500 having died making the dangerous journey.
thousands of refugees stuck on Greece - Macedonia border as new rules take hold.
The vast majority of the migrants have come via Turkey.
EU heads of government are expected to push Turkey to do more to prevent migrants from leaving its shores, by targeting human trafficking networks and repatriating so-called economic migrants -- people who have left their homelands in hopes of a better life, rather than out of fear for their lives.
In return, the EU will support Turkey in managing the millions of refugees the country has already taken in. It already hosts 2.6 million migrants.
Under a joint action plan agreed upon last year, the EU agreed to pay Turkey 3 billion euros ($3.3 billion) to support its refugee population and target people-smuggling networks -- a mission that has seen NATO warships deployed to eastern Mediterranean this year.
Turkish PM: 'Solidarity' only answer
Ahead of the summit in Brussels, Belgium, British Prime Minister David Cameron said in a statement that his priorities would be "breaking the link between getting on a boat and getting resettlement in Europe."
He proposed doing so by smashing trafficking gangs and stepping up the return of economic migrants, supporting Turkey and providing technical assistance to Greece to speed up the processing of migrant claims and repatriation of illegal migrants.
Also before the summit Monday, Turkish Prime Minister Ahmet Davutoglu said, "The only way to respond to this challenge is solidarity.
"At the end of the day, our continent is our continent altogether," he told reporters in Brussels.
A record 1.2 million people registered for asylum in the European Union in 2015 -- more than double the number from the previous year, the EU's statistics agency Eurostat said. Of those, Syrians, Afghans and Iraqis accounted for more than half of the first-time applicants.
Expert: Russia exploiting crisis
The summit comes as a desperate bottleneck of more than 10,000 people swells at the Greece-Macedonia border, and a senior NATO expert on strategic communications warned that a belligerent Russia was attempting to stir up emotions in Europe over the migrant influx.
NATO's Janis Sarts told CNN that Moscow appeared to be conducting an information war over the refugee issue, drumming up public anger to its own political ends.
"What we have seen is a lot of strong evidence to suggest that by deliberately distorting facts through their centrally controlled media, Russia is exploiting contentious issues in order to undermine European democratic values such as freedom of speech, tolerance and human rights," said Sarts, director of the NATO Strategic Communications Center of Excellence based in Riga, Latvia.
"Russia's political establishment has had no reservations about capitalizing on a potentially divisive issue such as refugees with a view to interfering in legitimate democratic processes outside of its own borders."
Buildup of migrants grows in Greece
Meanwhile, a major backlog of about 35,000 migrants has built up in Greece, a country already struggling under the weight of a debt crisis, following a decision by eight countries along the main overland migration route to Western Europe to all but close their borders in response.
Greece is the entry point into Europe for the overwhelming majority of the migrants, with arrivals averaging 1,800 a day last month.
On Monday morning, CNN's Arwa Damon reported from at a migrant camp at Idomeni, a village on the Greek border with Macedonia. Doctors without Borders said more than 11,000 people are crammed into the camp, which was designed as a transit camp for 1,500.
Authorities are letting only a few hundred Syrians and Iraqis through to Macedonia each day, raising fears that Greece is at risk of becoming a mass refugee camp.
Damon said those taking shelter in tents at Idomeni told her they hoped the Brussels meeting could result in the borders opening. But the reality is that there have been more barriers built than removed in the past six months.
Many said they had already experienced the effects of Ankara's efforts to crack down on migrants on the Turkish coastline, with some reporting having been turned back multiple times before they eventually made it across the Aegean Sea to Greece.
The Aegean, a stretch of the Mediterranean separating Turkey and Greece, is the main route that traffickers use to bring migrants into Europe.
Twenty-five migrants died in its waters Sunday in an attempt to reach Greece when their boat capsized off of Turkey's western coast, Turkey's semiofficial Anadolu news agency reported.