More than 30 people died off Turkey's coast attempting to reach Greece after two boats capsized today.

The deaths come as Turkey and Germany agree to a set of measures to try to tackle the Syrian refugee crisis, including a joint diplomatic initiative aimed at halting attacks against Syria's largest city.

Turkey's coast guard said 27 refugees died after their boat capsized in the Bay of Edremit, while four people were rescued. Further south, another 11 people died in a separate boat accident, according to the private Dogan news agency.

The coast guard has launched a search-and-rescue mission, including helicopters, to try to find 14 people who are reported to be missing.

The International Organization for Migration says 374 refugees and other migrants have died so far this year while trying to reach Greece.

Merkel 'horrified' by suffering in Syria

Turkish Prime Minister Ahmet Davutoglu, right, and German Chancellor Angela Merkel chat during a welcoming ceremony in Ankara, Turkey, on Monday. (Umit Bektas/Reuters)

German Chancellor Angela Merkel said after talks with Turkish Prime Minister Ahmet Davutoglu that she is "not just appalled but horrified" by the suffering caused by bombing in Syria, primarily by Russia.

Merkel said that Turkey and Germany will push at the United Nations for everyone to keep to a UN resolution passed in December that calls on all sides to halt without delay attacks on the civilian population.

Merkel was in Ankara for talks on how to reduce the influx of migrants into Europe, mostly via a perilous boat crossing from Turkey to Greece.

Merkel is under pressure at home to cut the number of refugee arrivals after nearly 1.1 million people were registered as asylum seekers in Germany last year.

Turkey for its part is under pressure from the EU to open its border to Syrians fleeing an onslaught by government forces in the city of Aleppo. Turkish Deputy Prime Minister Numan Kurtulmus said Monday the number of refugees amassing at the border could be as many as 600,000.

The Turkish border crossing of Oncupinar, opposite the Syrian Bab al-Salameh gate, remained closed for a fourth day on Monday as Turkish authorities provided assistance to the Syrians at a displaced persons camp nearby.

It was not clear if or when Turkey would let the group in. Turkey, already home to 2.5 million Syrian refugees, says it has reached its capacity to absorb refugees but has indicated that it will continue to take refugees in.

"We are worried that opening the gates will lead to an increase in refugees," said Burak Kacacaoglu, a spokesman for the non-governmental Islamic charity group IHH. "We are concerned about the air strikes, which are increasingly targeting civilian areas. This is what causes refugees."

​Aleppo 'de facto under siege'

Davutoglu said Aleppo "is de facto under siege. We are on the verge of a new human tragedy."

Turkish police officers guard the closed Turkish border crossing with Syria on the outskirts of the town of Kilis on Monday. Turkey is under pressure from the EU to open its border to thousands of Syrians who have massed along the frontier in the past few days. (Lefteris Pitarakis/Associated Press)

"No one should excuse or show tolerance toward the Russian air attacks that amounts to ethnic massacres by saying 'Turkey takes care of the Syrian refugees anyway,"' Davutoglu said. "No one can expect Turkey to take on the burden on its own."

Davutoglu said he and Merkel agreed that an emergency aid group from the two countries would help supply the Syrian refugees at the border.

He added that the refugees would be allowed in to Turkey "when necessary," without elaborating.

Merkel said the two leaders also discussed how to combine the work of Turkey's coast guard with that of the EU's Frontex border agency.

Call for EU quotas

Merkel stuck to her insistence that Europe will need to accept "quotas" of refugees arriving by legal channels as part of "burden sharing," and that the system needs to be worked out soon. She said that "we can't expect of Turkey that it stops everything on the one hand, and on the other hand say we'll talk about the quotas half a year from now."

Merkel pointed to the €3 billion the EU already has promised to Turkey and pledged to get the money flowing quickly."

Syrians line up as they wait to cross into Turkey at the Oncupinar border crossing in Kilis on Monday. (Osman Orsal/Reuters)

Turkey agreed in November to fight smuggling networks and help curb irregular migration. In return, the EU pledged €3 billion ($3.3 billion US) to help improve the condition of refugees, and to grant political concessions to Turkey, including an easing of visa restrictions and the fast-tracking of its EU membership process.

Turkey has since started to require Syrians arriving from third countries to apply for visas, in a bid to exclude those who aim to continue on to Greece.

Turkey has also agreed to grant work permits to Syrians as an incentive for them to stay in Turkey, and has announced plans to increase the capabilities of the coast guard and designate human smuggling as a form of organized crime — which would bring stiffer punishments.