The European Union is groping for ways to persuade Turkey to do more to keep Syrian refugees within its borders and stop them from flooding Europe amid deep mutual suspicion between Brussels and Ankara.

As a bitterly divided EU struggles to cope with hundreds of thousands of people fleeing war and poverty in the Middle East, Asia and Africa, securing the cooperation of Turkey, which is not a member of the EU, is seen as increasingly central to tackling the problem. The European Commission wants member states to increase and redirect EU financial help to support refugee housing, education and health services in Turkey, whose drive to join the bloc has made little progress over the past decade.

In return, Ankara would be expected to improve conditions for refugees, register more and take back more returned migrants. On top of this, it should fight human smugglers and increase efforts to stop Syrians from going to Greece.

From Ankara's perspective, Europe has woken up to the scale of the crisis only this year while Turkey has been on the frontline for more than four years. Ankara says it has spent $7.6 billion on food, shelter and care and has only received $417 million in international aid.

German Chancellor Angela Merkel said on Tuesday that Turkey must do more to defend its border with Greece. "Just Greece without the support of Turkey won't work," she said, noting she had spoken to Turkish President Tayyip Erdoğan by phone. At an emergency summit on Wednesday, Brussels will propose raising aid to Ankara from the EU budget to 1 billion euros ($1.1 billion) between now and the end of 2016, an EU source said. Two-thirds of this will be diverted from existing pre-accession funds that are available to Turkey as a country officially working to join the bloc. The commission will ask member states to match that money from national resources, generating a total of 2 billion euros. The EU is also mulling providing funding to other neighboring countries such as Jordan and Lebanon as well as U.N. agencies.

"It is not fair to expect Turkey to face the migratory flows alone," a Turkish Foreign Ministry official said. "No country is capable of tackling the illegal migratory flows alone."

European Council President Donald Tusk visited Turkey this month and officials plan to host Erdoğan at a mini-summit when he visits Brussels on Oct. 5. While the EU is willing to take in a share of Syrian refugees, it wants to keep as many as possible "close to their home," the Brussels euphemism for them staying in Turkey.