Meanwhile, thousands of Syrians lined up outside polling centers in government-controlled areas around the country to vote in the presidential election that Assad is widely expected to win but which has been denounced by critics as a sham.
The balloting comes amid a devastating, three-year civil war that activists say has killed more than 160,000 people, about a third of whom were civilians. It's also Syria's first multi-candidate election in more than 40 years.
The election is taking place only in areas under government control as much of northern and eastern Syria is in rebel hands. Tens of thousands of Syrians abroad voted last week, although many of the more than 2.7 million Syrian refugees across the region either abstained or were excluded by voting laws.
Assad, who is running for a third seven-year term and whose re-election is all but a foregone conclusion, faces two government-approved challengers in the race, Maher Hajjar and Hassan al-Nouri, both of whom were little known in Syria before declaring their candidacy for the country's top post in April.
In the Syrian capital, Damascus, security was tight with multiple rings of checkpoints set up around the city and its entrances. Troops searched cars and asked people for their IDs.
At a polling station in the city's Dama Rose hotel, many voters refused to go behind the curtain to vote in privacy, instead publicly circling Assad's name.
At the same station in central Damascus, a box with pins was available for those who wanted to prick their finger and vote in blood, a symbolic act of allegiance and patriotism.
At least three flights from Kuwait, chartered by an anonymous Syrian businessman, were to bring Syrian expats home to vote. The first flight landed in the morning hours with nearly 200 people, according to an Associated Press crew at the Damascus International Airport.
The people said they would vote and then immediately fly back to Kuwait.
But even as voting got under way in government-controlled parts of the country, activists reported fighting, shelling and air raids in rebel-held areas of Syria.
In the rebel-held central town of Rastan, which has been under attack by government forces for more than two years, an activist who goes by the name of Murhaf al-Zoubi said all the local residents "want Assad to go."
"There are no elections here, this is a free, liberated area," al-Zoubi said.
The Interior Ministry said there were 15.8 million eligible voters, both inside and outside Syria, and that 9,600 voting centers have been set up around the country.
REUTERS/AP