German Chancellor Angela Merkel and U.S. President Donald Trump share concerns about developments in Syria, especially the humanitarian situation in the region around Idlib, Merkel’s spokesman said after the two leaders spoke by telephone, Reuters reported.

“Russia is called upon to act in a moderating manner on the Syrian government and prevent a further escalation,” Steffen Seibert said in a statement on Monday evening.

Seibert said the two leaders also spoke about Ukraine, the Western Balkans and trade, he said, without elaborating.