Russia is defending a massive assault on a Damascus suburb by Syrian and Russian warplanes that an independent monitor says has killed at least 250 civilians in the last two days.
Russian Foreign Minister Sergey Lavrov appeared to endorse the assault, which he said was backed by Russian warplanes. "In keeping with the existing agreements, the fight against terrorism cannot be restricted by anything," he said.
The Damascus suburb of Ghouta harbors the Al-Nusra Islamist group, which is an affiliate of Al-Qaeda and a designated terrorist organization, Lavrov said in Moscow on February 20.
Lavrov said Al-Nusra had carried out "provocations," including attacking the Russian Embassy and trade mission in Damascus, and said Russia and Syria would draw from their experience bombing Aleppo in waging an all-out assault on the militants in Ghouta.
"The experience gained in Aleppo, when an agreement was reached with militants on their organized exodus, can be used in Eastern Ghouta," he said.
The United Nations, the United States, European countries, and human rights groups have decried the massive killing of civilians in 48 hours of bombing by Syrian and Russian warplanes and helicopter gunships.
Rescuers, monitors, and the UN say the bombs have hit hospitals, apartment blocks, markets, and other civilian targets.
The Syrian Observatory for Human Rights said at least 250 civilians, including 58 children, have been killed since the bombing began late on February 18, and another 1,200 people were wounded.
"We no longer have the words to describe children's suffering and our outrage," the UN children's agency said.
UN Secretary-General Antonio Guterres said late on February 20 through a spokesman that he was "deeply alarmed" by the escalating violence and its "devastating impact on civilians."
Residents of Eastern Ghouta "are living under extreme conditions, including malnutrition," he said.
U.S. State Department spokeswoman Heather Nauert said the United States was "deeply concerned" about the "siege and starve tactics" being used by Russia and Syria.
"The horrors of east Aleppo are being repeated in east Ghouta with the ongoing slaughter of trapped civilians and woefully inadequate access for humanitarian actors," she said.
"The cessation of violence must begin now, and those needing emergency assistance should be allowed to evacuate immediately," she said.
"We call on all parties to commit to the unconditional deescalation of violence. Russia must end its support of the Assad regime and its allies. They are responsible for the attacks, for the dire humanitarian situation in east Ghouta, and for the horrendous civilian death toll," Nauert said.
UN Syria envoy Staffan de Mistura warned that the escalating battle in Ghouta could turn into a repeat of the bloody fight for Aleppo, over which Damascus regained full control in late 2016 after years of fighting.
The Syrian Foreign Ministry accused militants in Ghouta of targeting Damascus and using people as "human shields."
Factions in Ghouta fired mortars at Damascus on February 20, killing six people and injuring 28, Syrian state TV said.
With reporting by AP, AFP, and Reuters