DAMASCUS: Syria said Friday a United Nations report accusing it of using sarin gas in an attack on the town of Khan Sheikhun in April was a "falsification of the truth".

"Syria categorically denies the content of the joint report between the UN and the Organisation for the Prohibition of Chemical Weapons," a foreign ministry statement said.

"This report and the one that preceded it are falsifications of the truth and distort the exact information on what happened at Khan Sheikhun."

More than 80 people died on April 4 when sarin gas projectiles were fired into Khan Sheikhun, a militant-held town in the Idlib province of northwestern Syria.

UN investigators on Thursday blamed the attack on President Bashar al-Assad's government.

The Syrian statement, quoted by official media, denounced the "method of investigation", saying it was based on "the words of the criminals who committed this immoral act in Khan Sheikhun and on dubious witnesses".

The ministry said the UN report was written on the basis of "instructions from the US administration and Western countries to exert more political pressure" on Damascus.

Images of the dead and dying in the aftermath of the attack provoked global outrage and a US cruise missile strike on a government air base.

The UN put the death toll at 83 while the Britain-based Syrian Observatory for Human Rights said 87 people were killed.