Global outrage as 'chemical attack' kills dozens in Syria

The attack on the town of Khan Sheikhun killed at least 72 civilians and saw dozens suffering respiratory problems and symptoms including vomiting, fainting and foaming at the mouth, the Syrian Observatory for Human Rights monitoring group said.

At least 20 children were among the dead, the Observatory said.

Hours after the initial attack, airstrikes also hit a hospital in the town where doctors were treating victims bringing down rubble on top of medics as they worked.

Syria's opposition blamed President Bashar al-Assad's forces, saying the attack cast doubt on the future of peace talks.

The opposition's National Coalition demanded the UN "open an immediate investigation" and hold those responsible to account.

"Failure to do so will be understood as a message of blessing to the regime for its actions," it said in a statement.

A senior Syrian security source denied claims of regime involvement as a "false accusation".

Russia's military, which has been fighting in support of Assad's government since September 2015, denied carrying out any strikes near the town.

The incident brought swift international condemnation.

UN envoy

UN Syria envoy Staffan de Mistura said the attack was believed to be chemical and launched from the air, adding that there should be a "clear identification of responsibilities and accountability".

"What we have understood, it was a chemical attack and it came from the air," de Mistura told reporters in Brussels.

The UN's Commission of Inquiry for Syria said it had begun investigating the "extremely concerning" reports of "alleged use of chemical weapons."

White House

The White House pinned the blame squarely on the Syrian regime.

"Today's chemical attack in Syria against innocent people, including women and children, is reprehensible," White House spokesman Sean Spicer said, adding the administration was "confident" in its assessment that Assad was to blame.

Turkey

Turkish President Recep Tayyip Erdogan telephoned his Russian counterpart Vladimir Putin, according to Presidential sources, to express his outrage at the attack.

Erdogan said "this kind of inhuman attack was unacceptable", adding that the attack threatened peace talks in the Kazakh capital Astana.

European Union

European Union diplomatic chief Federica Mogherini said the Assad government bore "primary responsibility" for the attack.

"Obviously there is a primary responsibility there of the regime because it has responsibility of protecting its people not attacking its people," she said.

Britain

British Foreign Secretary Boris Johnson called reports of the attack "horrific" and said the incident "must be investigated and perpetrators held to account".

"This bears all the hallmarks of an attack by the regime, which has repeatedly used chemical weapons," he said in a statement.

Erdogan said 'this kind of inhuman attack was unacceptable', adding that the attack threatened peace talks in the Kazakh capital Astana

France

French President Francois Hollande accused Assad's regime of committing a "massacre."

"Once again the Syrian regime will deny the evidence of its responsibility for this massacre," Hollande said in a statement.

"Those who support this regime can once again reflect on the enormity of their political, strategic and moral responsibility," he added.

Meanwhile, French Foreign Minister Jean-Marc Ayrault called for an emergency UN Security Council meeting over the attack, which he described as "monstrous."

UN watchdog

The global chemical arms watchdog said on Tuesday it was "seriously concerned" by reports of the attack.

The Organisation for the Prohibition of Chemical Weapons (OPCW) said it was "gathering and analysing information from all available sources".

More than 320,000 people have been killed in Syria since the conflict began in March 2011 with anti-government protests.