DAMASCUS, Syria (AP) -- Syria's government and rebels traded accusations Tuesday of a chemical attack on a northern village for the first time in the civil war, although the U.S. said there was no evidence it had happened.
The use of such weapons would be a nightmare scenario in the 2-year-old conflict that has killed an estimated 70,000 people, and the competing claims showed awillingness by both sides to go to new levels to seek support from world powers.
One of the international community's biggest concerns is that Syria's arsenal of chemical weapons could be used by one side or the other, or could fall into the hands of foreign jihadi fighters among the rebels or the Lebanese militant group Hezbollah, which is allied with the regime of President Bashar Assad.
President Barack Obama has declared the use, deployment or transfer of the weapons would be a "red line" for possible military intervention by the U.S. in the Syrian conflict.
The accusations emerged only a few hours after the Syrian opposition elected a prime minister to head an interim government that would rule areas seized by rebel forces from the Assad regime.
The state-run SANA news agency said "a missile containing a chemical substance" was fired at the village of Khan al-Assal in Aleppo province by "terrorists" -- the term it uses for rebels. Deputy Foreign Minister Faysal Mekdad said 31 people were killed.
SANA added that more than 100 others were wounded, some of them critically, and it published pictures showing casualties, including children, on stretchers in what appears to be a hospital ward. None showed signs of physical injuries.
"It is another crime to be added to the record of armed terrorist groups that are supported by some Arab countries and Western countries," Mekdad told reporters in Damascus.
To back up its claims of a chemical attack by the rebels, SANA pointed to videos posted on YouTube several months ago that purported to show regime opponents experimenting with poisons on mice and rabbits. The origin of the videos was not known.
The rebels quickly denied using chemical weapons and accused regime forces of doing so.
Maj. Gen. Adnan Sillu, who was previously among those in charge of Syria's chemical weapons training program before he defected to Turkey last year, accused the Assad government of firing a chemical weapon. "Only the regime has long range missiles capable of handling chemical agents," he said in comments to Arab broadcaster Al Arabiya.
The head of Syria's main opposition group, the Syrian National Council, said the group was still investigating the attack.
The Britain-based Syrian Observatory for Human Rights, which relies on a network of activists in the country, said a rocket attack on Khan al-Assal killed at least 26 people. The group's director, Rami Abdul-Rahman, said he had no information that chemical weapons were involved and said the rocket landed near a military installation.
The village lies just west of the city of Aleppo and 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 shells nearby villages.
The Aleppo Media Center, affiliated with the rebels, said there were cases of "suffocation and poison" among civilians in Khan al-Assal after a missile was fired at the area. It said in a statement the cases were "most likely" caused by regime forces' use of "poisonous gases."
Mohammed al-Khatib, an activist in Aleppo, said regime forces meant to target rebels but the missile landed in a government-controlled area of Khan al-Assal instead.
"It caused a huge explosion, like a Scud missile does," he said. "Everyone knows rebels only have primitive rockets. Claims that opposition fighters were behind the attack are laughable."
A U.S. official said there was no evidence either side had used chemical weapons.
The origin of the attack is still unclear, the official said, adding that the Organization for the Prohibition of Chemical Weapons also was reporting no independent information of chemical weapons use. The official wasn't authorized to speak publicly on the matter and spoke on condition of anonymity.
The White House and the State Department rejected only the Assad regime's charge.
White House spokesman Jay Carney said the U.S. is looking carefully at all allegations, but said the Obama administration is "deeply skeptical" of any claims by the Assad regime.
"This is an issue that has been made very clear by the president to be of great concern to us," Carney said, adding that if the Syrian regime does use such weapons, "there will be consequences."