At least person was killed and several more injured in shelling on the central Damascus Ummayad Square on Monday morning, Syrian state media reported.

State television said one person had been killed and others wounded, while official news agency SANA said "initial information suggests six citizens were wounded by terrorist shelling... on Ummayad Square."

Syria's fractious opposition, further weakened by the shock weekend resignation of its leader, must reunite to prevent extremists from taking over, the French foreign minister said Monday.

Laurent Fabius also told Europe 1 radio that he was aware of a rumor that President Bashar Assad had been assassinated by an Iranian bodyguard but said that the information published on a website "has not been confirmed."

Riad al-Asaad, commander of the rebel Free Syrian Army, was wounded overnight in a blast that hit his car in eastern Syria, the Syrian Observatory for Human Rights watchdog said on Monday.

A government official in Ankara confirmed Asaad had been hurt, saying he had lost a leg in the attack but that he was in "good condition" after being rushed across the Syrian border into Turkey for treatment.

Arab nations and Turkey, helped by the CIA, have dramatically increased military aid to Syrian rebels in recent months, The New York Times reported Monday.

The U.S. Central Intelligence Agency was helping their efforts, the newspaper added, citing air traffic data and interviews with unnamed officials and the rebel commanders.

The opposition will take over Syria's vacant seat at the Arab League, a high-ranking league official told Agence France Presse Monday, a day ahead of a leaders' summit in Doha.

"The opposition has been invited to the Arab summit and will occupy Syria's seat at the Arab League," the official said.

Members of Syrian President Bashar Assad's own Alawite sect gathered in Cairo on Sunday to announce their support for his overthrow in an unprecedented gathering.

The Alawites, joined by other minority representatives, said they wanted to disassociate their sect from Assad's brutal crackdown on the rebellion in which an estimated 70,000 people have been killed.

The opposition Syrian National Coalition has been invited to the Arab summit this week, bringing the rebels closer to filling Syria's seat in the Arab League, the group's Qatar envoy said Sunday.

The invitation was revealed as differences over the participation of the opponents of Syrian President Bashar Assad in the summit emerged during a ministerial preparatory meeting on Sunday.

U.S. Secretary of State John Kerry pressed Iraq to stop allowing Iranian flights apparently carrying military equipment through its airspace headed to Syria, on a surprise visit to Baghdad on Sunday.

Kerry warned Prime Minister Nuri al-Maliki that Washington was "watching what Iraq is doing", the highest-level criticism yet of Baghdad for not inspecting flights which Tehran insists are carrying humanitarian supplies.

A rumor about the death of Syrian President Bashar Assad was massively shared on social media websites on Sunday, the French weekly magazine Le Point reported.

"News about Assad being shot dead by his Iranian bodyguard have not been confirmed yet,” the magazine said, revealing that the opposition's Free Syrian Army has denied such reports.

Rebels fighting President Bashar Assad's regime have seized a 25-kilometer (15 miles) strip of land stretching from the Jordan border to the Israeli-occupied Golan Heights, a watchdog said on Sunday.

"Fighters loyal to Al-Nusra Front, Al-Yarmuk Brigade, Al-Mutaz Billah Brigade and others took control of Al-Rai military checkpoint," east of Sahem al-Golan town in the southern province of Daraa, said the Syrian Observatory for Human Rights.