Damascus will not use chemical weapons against its own citizens, or in the event of war with its neighbor Israel, Syria's Information Minister was quoted as saying on Wednesday.

A senior Israeli intelligence officer said on Tuesday that Syrian government forces had used chemical weapons against rebels fighting to overthrow President Bashar Assad.

But the assessment was met with skepticism by the United States, which has declared any use of chemical weapons in Syria's two-year-old civil war a "red line" that could trigger intervention.

Speaking In Cairo, U.S. Defense Secretary Chuck Hagel said on Tuesday that
the U.S. effort to determine whether Syria has used chemical weapons is a
"serious business" that cannot be decided in a rush just because several
countries believe evidence supports that conclusion.

"Suspicions are one thing, evidence is another," Hagel told reporters as he
wrapped up a visit to Egypt that included talks about Syria and other regional
issues.

"I think we have to be very careful here before we make any conclusions [and]
draw any conclusions based on real intelligence. That's not at all questioning
other nations' intelligence. But the United States relies on its own intelligence."

The Syrian government and rebels each accused the other of launching a chemical attack near the northern city of Aleppo last month.

Syria last year acknowledged that it had chemical and biological weapons and said it could use them if foreign countries intervened, a threat that was met with strong warnings from Washington and its allies.

Western countries and Israel have also expressed fears that chemical weapons could fall into the hands of militant groups hostile to them as Assad's authority erodes.

"Even if Syria does have chemical weapons, our leadership and our military will not use them either against Syrians or against Israelis, above all for moral reasons and secondarily on legal and political grounds," Syrian Minister of Information Omran al-Zoubi was quoted by Interfax news agency as saying at a Moscow university.

He said Syria would not resort to chemical weapons even if it had to go to war with Israel and use "all resources."

Also on Wednesday, a 1,000-year-old minaret at Aleppo's Umayyad Mosque collapsed due to clashes between Syrian rebels and forces loyal to Assad, activists and state media said.

Syria's civil war has cost more than 70,000 lives and has also damaged or destroyed many archaeological and architectural treasures, some of them United Nations world heritage sites, such as Aleppo's Old City where the mosque is located.

The opposing parties blamed the other for the toppling of the minaret, which predated the medieval-era mosque it stood in. Fighting has ravaged the Old City's stone-vaulted alleyways for months and had already reduced much of the mosque to rubble.

State news agency SANA accused the Nusra Front, an al-Qaida-linked rebel group, of bringing down the minaret. Opposition groups said army tank fire was to blame.

The conflict in Syria, now in its third year, threatens ancient castles and Roman ruins across the country.