Yemen's government has apologized to southern separatists and northern rebels for wars against them, seeking to encourage a national dialogue aimed at drafting a new constitution and holding elections.

The government "offers its regrets to the sons of the southern provinces," who are demanding autonomy or even independence, and to those of the north, where minority Shiite Muslims have been battling the central government since 2004, according to a statement published late Wednesday.

France is seeking a reaction with "force" if a massacre in Syria involving chemical weapons is confirmed, French Foreign Minister Laurent Fabius said Thursday, although he ruled out the use of ground troops.

"If it is proven, France's position is that there must be a reaction, a reaction that could take the form of a reaction with force," Fabius told BFM-TV.

Iran has rejected claims the Syrian regime, its chief regional ally, had deployed chemical weapons, saying if such an attack were proven rebels would be responsible, IRNA news agency said Thursday.

"If the information concerning the use of chemical weapons is accurate, very definitely they were used by terrorist groups... who have shown they will not hold back from committing any crime," Foreign Minister Mohammad Javad Zarif was quoted as saying, referring to rebels locked in a deadly war with President Bashar Assad's forces.

U.N. Security Council members are seeking "clarity" on opposition claims that Syrian troops used chemical weapons in an attack near Damascus, Argentina's U.N. envoy, the council president, said Wednesday.

U.N. Secretary General Ban Ki-moon's office said earlier he was "shocked" by the reports and that U.N. weapons experts in Syria to probe previous allegations were in discussions with Damascus.

British Foreign Secretary William Hague said Wednesday that he hoped the alleged chemical weapons attacks in Syria would "wake up" President Bashar Assad's supporters to the nature of his regime.

"I hope all members of the (U.N.) Security Council will join us," he told reporters before talks in Paris with French counterpart Laurent Fabius. "I hope this will wake up some who have supported the Assad regime, to realize its murderous and barbaric nature."

Israeli Defense Minister Moshe Yaalon said on Wednesday that the Syrian government had used chemical weapons, backing opposition claims of multiple deadly strikes around Damascus.

"In Syria, the regime has used chemical weapons and it's not the first time," Yaalon told Israeli defense correspondents.

A Tunisian rights group on Wednesday called for the release of Ridha Grira, the last defense minister of ousted dictator Zine El Abidine Ben Ali, who is suffering from cancer.

Detained since September 2011, Grira is being prosecuted for his part in a number of corruption cases linked to the Ben Ali regime, which was overthrown in a popular uprising in 2011.

The U.N. Security Council was to meet at 3:00 pm (1900 GMT) Wednesday over reports of a chemical weapons attack in Syria that allegedly killed hundreds, diplomats said.

U.N. Secretary General Ban Ki-moon's office said he was "shocked" by the reports of the attack and that U.N. inspectors in Syria to probe previous allegations were in discussions with Damascus.

The United States on Wednesday demanded "immediate access" for United Nations inspectors to the site of an alleged chemical weapons attack by government forces on civilians in Syria.

"We are working urgently to gather additional information," said White House spokesman Josh Earnest in a statement expressing deep concern over the reports.

Russia on Wednesday called Syrian opposition claims of the Damascus regime launching a chemical weapons attack that killed more than 1,300 people a "premeditated provocation."

The foreign ministry stressed that the reports were issued just as a U.N. chemical weapons inspection team had arrived in Syria and noted that "this makes us think that we are once again dealing with a premeditated provocation."