Syria will cooperate with visiting members of an international panel investigating a deadly April chemical weapons attack to prove it was not involved, the country's deputy foreign minister said Wednesday.

"In the coming few days we will receive a delegation from the... Joint Investigative Mechanism," which is investigating the sarin gas attack in a rebel-held northwestern town, Faisal al-Moqdad told reporters in Damascus.

"We will give them everything they want, to prove that Syria was not behind this terrible attack, which at the end of the day killed Syrians," he said.

"This comes within the framework of our firm and absolute conviction that Syria has not and will not use chemical weapons and the terrorists are the ones who use these weapons."

At least 87 people including over 30 children died in the April 4 attack on Khan Sheikhun, a town in the opposition-held province of Idlib.

Syria's government has denied involvement and claims it no longer possesses chemical weapons after a 2013 agreement under which it pledged to surrender its chemical arsenal.

The Organization for the Prohibition of Chemical Weapons earlier this year presented a report confirming sarin gas was used in the attack, but did not assign blame.

The JIM, a joint OPCW-United Nations panel, is now investigating the question of responsibility.

It says it has come under intense pressure in the process.

The head of the investigation complained in July of a "highly-politicised environment" and attempts to influence the probe.

Government ally Damascus has already cast doubt on the OPCW's conclusion that sarin gas was used in the attack, saying it was "based on rather questionable data".

Moqdad suggested Damascus would only accept results that absolved it of responsibility for the attack.

"If this investigation is built on well-known rules and foundations, it will prove once again that Syria has not and will not use chemical weapons," he said.

Source: AFP