U.S. Secretary of State Hillary Clinton Wednesday voiced support for ceasefire in Syria on the occasion of Muslim holiday Eid al-Adha, while again calling for "political transition" in the violence-plagued Mideast nation.

"We support his call for a ceasefire for the Eid al-Adha holiday so that Syrians could celebrate in peace," Clinton told reporters, referring to UN-Arab League joint special representative Lakhdar Brahimi's proposal made on Tuesday.

"We'd like to see the violence come to an end, there's no doubt about this, and we'd like to see a political transition take hold and begin," she said.

The Eid al-Adha festival, also known as Feast of the Sacrifice, is one of the holiest periods on the Muslim calendar. The four-day event begins on Oct. 26.

Brahimi said he would return to Syria after the holiday and "if we find out that this calmness is actually achieved during the Eid and continues, we will try to build on it."

However, observers see a slim chance for truce as the Syrian government and the opposition forces were still fought hard against each other in the capital of Damascus and northern parts of the country.

The rebels bolstered their strength recently after reportedly acquiring U.S.-made surface-to-air missiles.

Citing verified information, Russian Chief of General Staff Nikolai Makarov said Wednesday that the Syrian opposition has acquired portable air-defense systems produced abroad, including the U.S.-made Stingers.

The United States denied the assertion, saying it provided no lethal assistance to rebel forces whatsoever, including Stingers.

Despite the denial, Washington did boost its financial aid recently to those seeking to oust embattled President Bashar al-Assad.

In late September, Clinton announced that the Obama administration would provide the Syrian opposition with an additional 15 million U.S. dollars on non-lethal aid. The new pledge pushed total U.S. non-lethal aid to opposition groups to almost 45 million dollars.