World powers said a suicide bombing Wednesday that killed three top Syrian officials showed the urgent need for a political transition.

"The French government, without knowing the circumstances of this attack, has always condemned terrorism. That said, given the level of violence, this makes it even more necessary and urgent to find a political transition," French Foreign Minister Laurent Fabius told the French Senate.

Iran's Revolutionary Guards on Wednesday scoffed at U.S. claims that it could Gulf waters of mines in case of conflict, after Washington announced plans for a multinational anti-mine operation.

"The Americans boast a lot about many things, but they are facing problems in practice," General Mahmoud Fahimi, deputy chief of the Guards' naval forces, told the Fars news agency.

Russia on Wednesday said a decisive battle was in progress in Syria and rejected a Western-backed U.N. resolution on the crisis as it would mean taking sides with a revolutionary movement.

"A decisive battle is in progress in Syria. Adopting the resolution would mean outright support of a revolutionary movement. And if we are talking about a revolution then the United Nations has nothing to do with it," Foreign Minister Sergei Lavrov told reporters in reference to the armed opposition to President Bashar Assad.

The rebel Free Syrian Army head has echoed fears that President Bashar Assad might resort to using chemical weapons to try to rescue his embattled regime, Al-Bayan newspaper reported on Wednesday.

"We are seeking to secure protective gas masks for civilians and (defected) soldiers ... after the regime moved some out of storage," Colonel Riad Assaad told the Dubai daily.

A suicide bomber on Wednesday struck at the heart of Syria's security apparatus, killing the country's defense minister and President Bashar Assad's brother-in-law, state television said.

The attack, which for the first time in a 16-month anti-regime uprising targeted members of Assad's inner core, came hours ahead of a U.N. Security Council debate on Syrian sanctions, when a showdown between Western powers and Russia and China is expected.

A Russian ship that tried to supply attack helicopters to Syria last month before being forced back will dock in Saint Petersburg in coming days, its owners said on Wednesday.

The privately-chartered Alaed had to return to Russia after its initial attempt to deliver the controversial cargo to President Bashar Assad's regime in June was exposed by the U.S. State Department.

Avigdor Lieberman, whose ultra-nationalist Yisrael Beitenu is a key member of Israel's ruling coalition, on Wednesday said he had no intention of leaving government a day after the Kadima party withdrew.

Despite differences with Israeli Prime Minister Benjamin Netanyahu over plans to expand the military conscription law to include more ultra-Orthodox Jews, Lieberman, who is also foreign minister, said he had no intention of quitting the coalition.

More than 60 soldiers have been killed in clashes with the rebel Free Syrian Army in Damascus in the past 48 hours, the Syrian Observatory for Human Rights said on Wednesday.

"Between 40 and 50 soldiers of the regular Syrian forces were killed the day before yesterday (Monday) in fighting in Damascus, and at least 20 were killed yesterday," the Observatory's Rami Abdel Rahman told Agence France Presse.

Two Syrian brigadier generals crossed into Turkey overnight, a Turkish foreign ministry official told Agence France Presse Wednesday.

"Some 330 Syrians including two brigadier generals fled to Turkey Tuesday night," the official said.

U.N. chief Ban Ki-moon on Wednesday urged the Security Council to act to stop the bloodshed in Syria, after holding talks with Chinese leaders in Beijing hours ahead of a vote on fresh sanctions.

The Security Council will on Wednesday vote on a Western resolution renewing the U.N. mission in the country that calls for sanctions if the regime does not pull back heavy weapons.