Germany on Monday called for further talks between the EU and Turkey to better address the refugee crisis amid escalating tensions in northwestern Syria.

Speaking at a news conference in Berlin, Chancellor Angela Merkel’s spokesman Steffen Seibert said they were well aware of criticisms of Ankara on the implementation of the 2016 EU-Turkey refugee agreement.

“We must talk with Turkey on these issues. We must also talk about the additional concerns and burden due to the hundreds of thousands of displaced people in Syria,” he said, referring to the humanitarian crisis in the northwestern Syrian province of Idlib.

Seibert argued that despite several problems, the EU-Turkey refugee agreement has been successful so far in controlling irregular migration, countering human smugglers and saving human lives in the Aegean Sea.

“The Federal Government remains convinced that the EU-Turkey agreement is in the interest of both sides, it helps both the EU and Turkey, it should be preserved and observed,” he said.

As part of the agreement, the EU had promised €6 billion ($6.8 billion) of aid for 2016-2019 to improve living conditions of more than 3 million Syrian refugees in Turkey. But so far, only €4.7 billion were contracted and €3.2 billion disbursed.

The EU’s bureaucratic hurdles and delays to mobilize promised funds led to sharp criticism by Turkish politicians.

Ankara also criticized its European partners for not fully implementing the 2016 agreement, and backing away from their political commitments.

As part of the deal, the EU had promised to accelerate talks on Turkey’s EU membership and visa-free travel for Turkish nationals within the Schengen area.

Turkey already hosts some 3.7 million migrants from Syria alone, more than any other country in the world.