DUBAI: The head of the United Nations chemical weapons inspectors in Syria said on Wednesday reports of a nerve gas attack killing more than a 100 people near Damascus should be investigated.

Syria's main opposition group accused President Bashar al-Assad's regime of killing more than 1,300 people in a chemical weapons attack Wednesday on rebel areas near Damascus.

The claim of a chemical attack, which could not be independently verified, was vehemently denied by the Syrian regime which said it was intended to hinder the mission of UN chemical weapons inspectors now in the country.

Swedish scientist Ake Sellstrom told news agency TT that while he had only seen TV footage, the high number of casualties reported sounded suspicious.

The National Coalition's George Sabra, who spoke to reporters in Istanbul, also said the attack was a “coup de grace that kills all hopes for a political solution in Syria.”

“It sounds like something that should be looked into,” he told TT by phone from Damascus. “It will depend on whether any UN member state goes to the secretary general and says we should look at this event. We are in place.”

Earlier, the opposition Syrian National Coalition called for an urgent UN Security Council meeting an alleged gas attack by the army killed scores of people in the restive country.

“I call on the Security Council to convene urgently,” National Coalition leader Ahmed al-Jarba told Al-Arabiya news channel, condemning the Syrian army's bombardment of the Ghouta suburbs of Damascus as a “massacre.”

He urged the UN commission of inquiry on the use of chemical weapons to visit the site.

In Cairo, the Arab League urged UN inspectors now in Syria to visit the site of the alleged attack immediately.

The Britain-based Syrian Observatory for Human Rights said at least 100 people were killed in fierce army bombardment of the rebel stronghold, adding that the figure “will surely go up.”

It did not comment on allegations by anti-regime activists that the army had used chemical weapons.

According to activists, almost 500 people died of gas inhalation and exposure to chemical weapons.

Syrian authorities denied charges that the army used chemical arms.