A drone attack on a Syrian military academy graduation ceremony killed at least 80 people and injured more than 240.
In one of the deadliest recent attacks, the strike killed women, six children and army personnel in Homs.
Syria said in a statement drones laden with explosives targeted the ceremony packed with young officers and their families as it was about to end on Thursday.
Without naming any particular group, the military accused insurgents “backed by known international forces” of the attack and said “it will respond with full force and decisiveness to these terrorist organisations, wherever they exist”.
Health Minister Hassan al-Ghabash said there were concerns the death toll could rise as many of the wounded were in serious condition.
There was no immediate claim of responsibility from the rebels and jihadists battling the government in the country’s 13-year civil war.
A graphic video of the aftermath of the attack showed dozens of casualties and their relatives screaming for help inside a large, walled parade ground. Gunfire can also be heard in the background.
UN Secretary-General Antonio Guterres “expressed deep concern” about the drone attack in Homs as well as reports of retaliatory shelling in northwest Syria. He condemned all violence and called for a nationwide ceasefire, a spokesperson added.
Syria’s state television said the government announced a three-day state of mourning starting Friday.
The Britain-based Syrian Observatory for Human Rights, an opposition war monitor, and the pro-government Sham FM radio station earlier reported the strikes.
Syria’s crisis started with peaceful protests against President Bashar Assad’s government in March 2011 but quickly morphed into a full-blown civil war after the government’s brutal crackdown on the protesters.
