At least 100 people were killed on Thursday in an attack on a military academy in Syria with weaponised drones bombing the site minutes after Syria's defence minister left a graduation ceremony there.
Civilians and military personnel were killed in the attack on the academy in the central province of Homs, Syria's defence ministry said in a statement, adding "terrorist" groups had used drones to carry it out.
The statement did not specify an organisation and no group immediately claimed responsibility for the attack.
Syria's defence and foreign ministries vowed in written statements to respond "with full force" to the attack. Syrian government forces have carried out heavy bombings on the opposition-held zone of Idlib throughout the day.
"After the ceremony, people went down to the courtyard and the explosives hit. We don't know where it came from, and corpses littered the ground," said a Syrian man who had helped set up decorations at the academy for the occasion.
Syria's conflict began with protests against President Bashar al-Assad in 2011 but spiralled into an all-out war that has left hundreds of thousands dead and millions displaced.
Assad regained most of the country, but a swathe in the north bordering Turkey is still held by armed opposition groups.
164 confirmed dead after two major earthquakes strike Venezuela
Europeans told to protect themselves as deadly heatwave takes its toll
Trump asks Congress for more funds to fight Iran, defying rebuke on war powers
Magnitude 6.9 quake strikes Japan's northeast, no tsunami warning
US, Iran at odds on nuclear inspections, frozen assets in deal to end war
