DAMASCUS, Syria (AP) — Syria's government accused rebels of firing a chemical weapon on Tuesday for the first time in the 2-year-old civil war, calling it the "first act" of a newly announced opposition interim government.

Rebels quickly denied the report and accused regime forces of firing the chemical weapon. Neither of the accusations could immediately be verified.

Information Minister Omran al-Zoubi said 16 people were killed and 86 wounded in the missile attack on the village of Khan al-Assal near the city of Aleppo.

If confirmed, it would mark the first time such weapons have been used since the uprising against President Bashar Assad began in March 2011.

One of the international community's top concerns since fighting began is that Syria's vast arsenal of chemical weapons could be used by one side or the other or could fall into the hands of foreign jihadist fighters among the rebels or the Lebanese militant group Hezbollah, which is allied with the regime.

The minister al-Zoubi said the missile containing "poisonous gases" was fired from Nairab district in Aleppo into Khan al-Assal village.

The reported attack was in an area just east of the city of Aleppo that had seen fierce fighting for weeks before rebels took over a sprawling government complex there last month.

The facility included several military posts and a police academy that Assad's forces have turned into a military base that regularly fires shells at nearby villages.

In comments made to the pro-government Al-Ikhbariya TV station, the information minister held the international community responsible for arming the rebels and described it as a "dangerous escalation."

"This is the first act by the government announced in Istanbul," he said.

Syria's opposition coalition early Tuesday elected a little-known American-educated IT manager to head an interim government to administer areas seized by rebel forces from Assad's troops.

In his first speech after his election, Hitto ruled out dialogue with the regime.

"We confirm to our people that there is no place for dialogue with the Assad regime," he said in a speech to media and members of the opposition Syrian National Coalition in Istanbul.

He said the interim government will be headquartered in rebel-held territories in northern Syria and urged international recognition for the new entity.

Anti-regime activists denied the government allegations of using chemical weapons.

An activist in Khan al-Assal said rebels had recently seized much of the village including a facility that housed a military academy.

The Aleppo Media Center, affiliated with the rebels, said there were cases of "suffocation and poison" among civilians in Khan al-Assal after a surface-to-surface missile was fired at the area. It said in a statement the cases were "most likely" caused by regime forces' use of "poisonous gases."

An activist in Aleppo province who identified himself as Yassin Abu Raed, not his real name, confirmed the attack and said there were at least 40 cases of suffocation in the area and several deaths.

But he said no details were available as casualties were being taken to a government-controlled area in Aleppo.

Abu Raed declined to give his real name because of security concerns.

He said it did not make sense for the rebels to fire a chemical weapon at an area they had recently seized, and accused the government instead.

"Why would the Free Syrian Army bomb themselves with a chemical weapon?" he asked.

As rebels make gather momentum with the capture of military bases and other strategic sites, concerns have mounted over the security of the chemical weapons arsenal.

U.S. Secretary of State John Kerry said recently that the longer the war goes on, the greater the danger of its institutions collapsing and extremists getting their hands on chemical weapons arsenal.

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Karam reported from Beirut. Ben Hubbard contributed to this report from Istanbul, Turkey.