BEIRUT, Oct 5 (AFP) - An attack on Thursday (Oct 5) on a Syrian military academy killed 112 people, a war monitor said, with state media blaming "terrorist organisations" for the drone strike in government-held Homs.

Separately, Turkish air raids in the country's Kurdish-held northeast killed at least 11 people, according to Kurdish forces, after Ankara had threatened retaliation for a bomb attack.

In the central city of Homs, "armed terrorist organisations" targeted "the graduation ceremony for officers of the military academy", an army statement carried by the official news agency SANA said.

The Syrian Observatory for Human Rights, a Britain-based monitor, reported "112 dead including 21 civilians, 11 of them women and girls". It said at least 120 people were wounded.

Health Minister Hassan al-Ghobash told state television the "preliminary" toll was 80 dead "including six women and six children" and around 240 wounded.

There was no immediate claim of responsibility.

The attack was carried out with "explosive-laden drones", according to the military statement, vowing to "respond with full force". The government declared three days of mourning starting Friday.

In the rebel-held Idlib region, residents reported heavy bombardment by government forces in apparent retaliation. The Observatory said eight people had been killed and some 30 wounded.

Swathes of Idlib province are controlled by Hayat Tahrir al-Sham, led by Al-Qaeda's former Syria branch. The jihadist group has used drones to attack government-held areas in the past.

United Nations chief Antonio Guterres was "deeply concerned" over the drone attack and the retaliatory shelling, his spokesman Stephane Dujarric said.

Geir Pedersen, the UN special envoy for Syria, said in a statement: "Today's horrific scenes are a reminder of the need to immediately de-escalate violence, towards a nationwide ceasefire and a cooperative approach to countering Security Council-listed terrorist groups."

Overnight, Syrian shelling killed an elderly woman and four of her children in a rebel-held area of Aleppo province, rescue workers and the Observatory said.