— Turkey and Germany agreed Monday on 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.

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 to keep to a 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. Turkey’s coast guard said Monday that 24 migrants died after their boat capsized in the Bay of Edremit, while four people were rescued.

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 European Union to allow the passage of up to 35,000 Syrians who have massed along the border in the past few days fleeing an onslaught by government forces in the city of Aleppo. 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 nearby camp for the displaced.

It was not clear whether 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 Kara­caoglu, a spokesman for the nongovernmental Islamic charity group IHH. “We are concerned about the airstrikes, which are increasingly targeting civilian areas. This is what causes refugees.”

Merkel said, “We have been, in the past few days, not just appalled but horrified by what has been caused in the way of human suffering for tens of thousands of people by bombing — primarily from the Russian side.”

“Under such circumstances, it’s hard for peace talks to take place, and so this situation must be brought to an end quickly,” Merkel said.

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

“No one should excuse or show tolerance toward the Russian air attacks that amount 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 had agreed that an emergency aid group from the two countries would help supply the Syrian refugees at the border.

He added that they would be allowed into 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 E.U.’s Frontex border agency. She said they will use an upcoming NATO defense ministers meeting to discuss “to what extent NATO can be helpful with the surveillance situation at sea” and support the coast guard’s and Frontex’s work.

— Associated Press