Results from post-mortems performed on victims of an attack in northern Syria show that chemical weapons, possibly sarin, were used, Turkey has said.

Tuesday's attack in Khan Sheikhoun in Idlib province killed more than 80 people, including up to 30 children, according to the Britain-based Syrian Observatory for Human Rights monitoring group.

Some 32 victims were brought to Turkey where three later died in hospital and underwent the examination.

"The results of the post-mortems confirm chemical weapons were used," Justice Minister Bekir Bozdag was quoted as saying by state-run Anadolu news agency.

"This scientific investigation also confirms that Assad used chemical weapons," he claimed, without giving further details.


Later, the country's health ministry said the results pointed to possible exposure to sarin.

The bodies were examined by officials from the World Health Organisation in the southern province of Adana together with officials from Organisation for the Prohibition of Chemical Weapons.

The attack sparked global outrage, with Angela Merkel calling it "barbaric" and saying indications suggest President Bashar al Assad was behind it.

Graphic content: Syrian father mourns his dead baby twins

The Syrian government has denied ever using chemical weapons against "our people" or "terrorists".

Syrian Foreign Minister Walid al Moalem said the army bombed an arms depot belonging to al Qaeda affiliate, the al Nusra Front, now known as the Fateh al Sham Front - echoing an earlier claim by the Russian defence ministry.

He told a news conference that Islamic State had also been storing chemical weapons from Iraq and Turkey.

Moments earlier, Russia said it was "premature" to accuse Damascus of using chemical weapons and called for a thorough investigation into the atrocity.

It has said the deaths and injuries were caused by a Syrian airstrike on a "terrorist warehouse" containing "toxic substances".

Witnesses described seeing victims of the attack choking, fainting and foaming at the mouth.

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Image: Bashar al Assad pictured during his latest interview

A defiant Mr Assad said in an interview: "We do not have any other option except victory.

"If we do not win this war, it means that Syria will be deleted from the map.

"We have no choice in facing this war, and that's why we are confident, we are persistent and we are determined," he told Croatian newspaper Vecernji List.

He was not asked about the suspected chemical attack, a text of the interview published by Syrian state news agency SANA showed.

British Foreign Secretary Boris Johnson said a United Nations resolution should be passed before any unilateral action was taken on Syria.

"I cannot understand how anybody on the UN Security Council could fail to sign up to a motion condemning the actions of the regime that is almost certainly responsible for that crime," he said.

Syria attack: Will Putin listen to Trump?

Donald Trump has criticised Russia and suggested the US may take on a more forceful role in Syria.

The President described the attack as an "affront to humanity" which "crossed many, many lines" and had changed his attitude on dealing with the conflict, but he stopped short of saying how he would tackle the crisis.

In an interview with The New York Times, he also said Moscow's role in the long-running civil war was "disappointing" - adding it was a "very sad day for Russia because they're aligned".

Jan Egeland, the United Nations' special envoy to Syria, said he welcomed the renewed interest from the US, but said a political solution also required Russian support.