A wave of nighttime airstrikes hit a hospital in Syria supported by Doctors Without Borders and nearby buildings in the rebel-held part of the contested city of Aleppo, killing as many as 27 people, including 14 doctors and patients — among them children and one of the last pediatricians in war-torn Syria, the international medical aid group reported.

The strikes, blamed on the embattled government in Damascus, came shortly before midnight Wednesday and hit the well-known al-Quds field hospital in the rebel-held district of Sukkari in Aleppo, according to opposition activists and rescue workers. A separate blitz in Aleppo reportedly killed 20, raising the 24-hour death toll in the key city to at least 61.

The chief Syrian opposition negotiator Mohammed Alloush blamed the government of President Bashar Assad for the deadly airstrikes. He told The Associated Press that the latest violence by government forces shows negotiations, such as the February talks that led to a short-lived cease fire, are not realistic.