Turkey and the European Union have joined international calls for Russia and Iran to "stop" Syrian government forces from carrying out a military offensive on the rebel-held enclave of eastern Ghouta, a suburb of Damascus where more than 400 civilians have reportedly been killed since February 18.
The calls by Turkish Foreign Minister Mevlut Cavusoglu and EU foreign-policy chief Federica Mogherini came hours ahead of a February 23 United Nations Security Council vote on a Western-drafted resolution demanding a 30-day truce in Ghouta.
"The massacre in eastern Ghouta must stop now," Mogherini said in a statement. "The European Union is running out of words to describe the horror being experienced by the people of eastern Ghouta."
Cavusoglu said earlier on February 23 that "Russia and Iran must stop the regime."
He also said that the bombardment of eastern Gouta and a government offensive against rebel-held positions in Idlib Province was "contrary" to agreements negotiated in Astana by diplomats from Ankara, Moscow, and Tehran.
Earlier, the United States criticized Russia over the bombing of eastern Ghouta, saying Moscow had a "unique responsibility" for more than 400 people being killed in the Damascus suburb this month.
The U.S. State Department called on Russia to use its influence over the Syrian government to stop the killing while U.S. diplomats pushed for a resolution demanding a 30-day truce in Ghouta that was scheduled for a vote in the UN Security Council early on February 23.
State Department spokeswoman Heather Nauert blamed Russia for not curbing Syrian President Bashar al-Assad and his army, which launched an all-out offensive to defeat militants in Ghouta in February -- an operation that Russia and Syria said would mirror their bloody campaign to retake Aleppo.
"What are they doing to stop the devastation, the deaths, the murders that are taking place in Syria?" Nauert asked journalists in Washington. "Without Russia backing Syria, the devastation and the deaths would certainly not be occurring."
"It is a good reminder that Russia bears a unique responsibility for what is taking place there," she said.
Nauert also blamed Moscow for what she called "throwing a wrench" into negotiations at the UN over a resolution to establish a temporary cease-fire that would allow aid to get to the civilian population that is trapped in Ghouta amid the fierce fighting.
Russia's UN ambassador rejected the Western-drafted resolution, raising the possibility of a veto when the council votes on it on February 23.
Ambassador Vasily Nebenzya said the media and Western nations were conducting a "misinformation campaign" about the fighting in Ghouta and ignoring what he called the "inconvenient truth" that several thousand fighters from a group affiliated with Al-Qaeda reside there.
Nauert said the fighting in Ghouta shows the failure of Russian-sponsored peace negotiations over Syria, which had designated eastern Ghouta as a "de-escalation zone" where fighting was supposed to be on the decline.
"It shows what a farce this de-escalation zone has become," Nauert said.
At the United Nations, U.S. Ambassador for Economic and Social Affairs Kelley Currie said Assad was trying to "bomb or starve" his enemies into submission in Ghouta, just as he did in Aleppo, Hama, and Homs.
She said Assad was counting on Russia to provide the cover he needs at the UN so his forces can "keep bombing and gassing these 400,000 people" who live in Ghouta.
The Syrian Army dropped leaflets on February 22 calling on Ghouta residents to leave for their own safety and urging opposition fighters to hand themselves over.
The leaflets were similar to those dropped over rebel-held neighborhoods during the government's siege of Aleppo.
Syria's UN Ambassador Bashar al-Ja'afari told the UN Security Council that Ghouta would be the "second Aleppo."
With reporting by AP, AFP, and Reuters