By Laurence Norman in Brussels and Emre Peker in Istanbul 

The European Union and Turkey have reached an agreement on how to stem the flow of refugees into the bloc, European Council President Donald Tusk said on Sunday, as he urged EU leaders to back the deal at today's Brussels summit.

"Our main goal is to stem the flow of migrants into Europe," Mr. Tusk said as he arrived at the meeting. "After many weeks of hard work...we have reached an agreement which I hope will be accepted by all parties concerned."

Mr. Tusk said he hopes Sunday's meeting will "re-energize" often strained ties between the EU and Turkey, which he called a "key partner" of the bloc.

At the heart of the proposed migration deal is Turkey's promises of tightening its border controls in exchange for some EUR3 billion ($3.19 billion) in cash and other benefits from the EU. Those prizes include speeding up work on Turkey's EU membership bid and a new push to help Ankara win visa-free access to the bloc for its citizens.

The EU has been pressing Turkey to boost controls at its sea border with Greece, which has been the dominant entry point for migrants and refugees into the bloc in recent months. Sunday's summit, where most EU leaders will be present, is expected to activate a detailed joint-action plan to stem the flow of migrants.

However, underlining the continued lack of trust between Ankara and Brussels, much of the focus ahead of Sunday's summit has been on how to guarantee the other side will keep to their pledges. One source of concern for the EU: the absence of Turkey's President Recep Tayyip Erdogan at Sunday's meeting.

EU officials spent the weekend trying to persuade Cyprus, which has long blocked progress on Turkey's EU membership bid over Ankara's refusal to recognize the Nicosia government, to sign up for the migration deal.

The talks between EU and Turkey started in September as the 28-nation bloc struggled with the biggest influx of migrants since the aftermath of World War II. Already this year more than 700,000 migrants, mainly Syrian, arrived in the EU via Turkey according to the International Organization of Migration.

Under the deal which has been negotiated, Turkey would beef up its patrols in the Aegean Sea and on the land borders with Greece and Bulgaria to stop illegal migration into Europe. They would also commit to crack down on human-trafficking gangs and would agree to take back to Turkey migrants whose asylum claims are denied by EU countries.

The first EU-Turkey summit in 11 years comes as Ankara faces diplomatic and security challenges from Moscow following the downing of a Russian warplane on Tuesday.

While a joint response to the refugee crisis is top of the agenda, the Turkish delegation led by Prime Minister Ahmet Davutoglu will also press European counterparts on broader geopolitical issues led by the Syrian conflict, the fight against Islamic State, and Russia's increasingly assertive military operations in support of the Damascus regime just south of Turkey's border.

Before flying to Brussels for the summit, Mr. Davutoglu said Russia and Iran were propping up embattled Syrian President Bashar al-Assad under the guise of fighting Islamic State, warning that indiscriminate bombing campaigns were also hitting civilians and threatening to unleash another wave of refugees.

"This matter is of direct interest to Turkey in the context of the refugee crisis, which is the main topic at the Turkey-EU summit," Mr. Davutoglu said.

The premier added that he will also discuss Russia's repeated violations of the Turkish airspace with EU leaders, and the tensions triggered by Turkey's downing of a Russian jet this week. "This carries great importance with regards to creating a common stance in the Turkey- EU-Russia triangle," he said.

On Thursday, Turkey's EU Affairs Minister Volkan Bozkir said Ankara and Brussels would start talks on a policy area covering economic and monetary policies as soon as Dec. 14-15. Turkey and the EU have started negotiations on 14 of the 35 policy criteria that Ankara must fulfill to join the bloc, opening the latest chapter in November 2013 after a three-year lull. The two parties are working to open discussions on five to six chapters next year, Mr. Bozkir said.

While the refugee crisis has strengthened Ankara's hand in negotiations, domestic developments in Turkey are complicating its efforts.

Two prominent Turkish journalists were jailed Thursday in connection with a controversial report on Turkey's arms shipments to Syrian rebels, which the government had repeatedly denied.

Their arrests, pending trial, was the latest crackdown agains press freedom and comes on the heels of the government's seizure of opposition media outlets in the lead up to early elections in November. The U.S. and EU have both sharply criticized the moves.

Write to Laurence Norman at laurence.norman@wsj.com and Emre Peker at emre.peker@wsj.com

(END) Dow Jones Newswires

November 29, 2015 08:56 ET (13:56 GMT)