The European Union's top diplomat has written to the foreign ministers of Russia, Iran and Turkey urging them to uphold a ceasefire in eastern Ghouta and allow aid into besieged areas.
Appealing to the trio as the leaders of the Syrian peace talks in the Kazakh capital Astana, EU foreign policy chief Federica Mogherini called on them to "implement a genuine humanitarian pause for at least 30 consecutive days throughout Syria."
In the Feb. 26 letter seen by Reuters, Mogherini also urged Russia, Turkey and Iran to "take all necessary steps to ensure that the fighting stops, that the Syrian people are protected, and finally that urgent humanitarian access and necessary medical evacuations are taking place."
Mogherini said in the letter, which was also sent to all 28 EU foreign ministers and to the secretary-general of the United Nations Antonio Guterres, that a ceasefire would give a chance for U.N.-led peace talks to make progress.
After helping turn the tide of the war in Syria in favour of its ally President Bashar al-Assad, Russia has cast itself as a Middle East peace broker.
Mogherini appealed to Moscow to make good on a July agreement for "de-escalation" zones, saying the United Nations Security Council resolution for a 30-day countrywide ceasefire was an opportunity to "consistently implement the spirit of the decisions taken in Astana."
As the region's top aid donor, the European Union believes it can use an international conference on Syria in Brussels on April 24-25 to persuade Moscow to stop the fighting if it wants international money to rebuild Syria.
"The EU will continue to play its part fully and to mobilise all political and humanitarian tools at its disposal," Mogherini said in the letter.
A donor's conference last year for Syria saw the European Union pledge 1.2 billion euros ($1.5 billion) for 2017 and the bloc, as well as some 70 other countries, is expected to offer fresh money this year.