US Secretary of State Hillary Clinton appealed to Syrians in the military and business who are still supporting Assad to abandon the embattled leader.
Clinton said at a news conference in Morocco on Sunday that she had a message for those holdout backers.
She said "the longer you support the regime’s campaign of violence against your brothers and sisters, the more it will stain your honor. If you refuse however to prop of the regime or take part in attacks... your countrymen and women will hail you as heroes."
However, Emirati authorities cancelled the residencies of dozens of Syrians for taking part in a protest against their regime outside the consulate in Dubai, Syrian activists told AFP on Sunday.
Two of them have already fled the Gulf country, arriving in Cairo on Saturday, after "all efforts failed to convince Emirati authorities to retract the decision," one of the activists said.
The Syrian Observatory for Human Rights said a military bombardment of opposition districts in Homs, now in its fourth week, had killed nine civilians, while rebel fighters had killed four soldiers in clashes in the city.
The British-based Observatory said eight civilians and 10 members of the security forces were killed in violence elsewhere in Syria, scene of what has become an increasingly militarized revolt against four decades of Assad family rule.
Voting was under way in the referendum on a new constitution, which Assad says will lead to a multiparty parliamentary election in three months, but his opponents see as a sick joke given Syria’s turmoil. The West also dismissed the vote as a "sham."
"What should we be voting for, whether to die by bombardment or by bullets? This is the only choice we have," said Waleed Fares, an activist in the Khalidiyah district of Homs.
"We have been trapped in our houses for 23 days. We cannot go out, except into some alleys. Markets, schools and government buildings are closed, and there is very little movement on the streets because of snipers," he said.
He said another besieged and battered district, Baba Amro, had had no food or water for three days. "Homs in general has no electricity for 18 hours a day." With most foreign reporters barred from Syria or heavily restricted, witness reports are hard to verify.
The Interior Ministry acknowledged obliquely that security conditions had disrupted voting, saying: "The referendum on a new constitution is taking place in a normal way in most provinces so far, with a large turnout, except in some areas."
The Syrian government, backed by Russia, China and Iran, and undeterred by Western and Arab pressure to halt the carnage, says it is fighting foreign-backed "armed terrorist groups." The outside world has been powerless to restrain Assad’s drive to crush the 11-month-old revolt, which has the potential to slide into a sectarian conflict.
Unwilling to intervene militarily and unable to get the UN Security Council to act in the teeth of Russian and Chinese opposition, Western powers have imposed their own sanctions on Syria and backed an Arab League call for Assad to step down.
US Secretary of State Hillary Clinton warned on Sunday of the perils of any foreign intervention.
"I think there is every possibility of a civil war. Outside intervention would not prevent that, it would probably expedite it," she told BBC. German Foreign Minister Guido Westerwelle said the referendum was "nothing but a farce."
"Sham votes cannot contribute to a solution of the crisis. Assad needs to put an end to the violence and clear the way for a political transition," he said in a statement. The military onslaught on parts of Homs has created harrowing conditions for civilians, rebels and journalists.
A video posted by activists on YouTube showed Mohammad Al-Mohammad, a doctor at a makeshift clinic in Baba Amro, holding a 15-year-old boy hit in the neck by shrapnel and spitting blood.
"It is late at night and Baba Amro is still being bombarded. We can do nothing for this boy," said the doctor, who has also been treating Western journalists wounded in the city.
In Hama, another city with a bloody record of resistance to Baathist rule, one activist said nobody was taking part in the referendum. “We will not vote on a constitution drafted by our killer," he said by satellite telephone, asking not to be named.
More than 80,000 Syrian refugees have fled the nearly 11 months of violence in their homeland and settled in neighboring Jordan, a Jordanian government official said Sunday.
The skyrocketing number of refugees, which was significantly higher figures than previously reported by the Jordanian government, attests to the growing violence in Syria where President Bashar Assad is trying to suppress a months-long rebellion by Syrians demanding he step down.
Jordanian Information Minister Rakan Al-Majali said Sunday that 73,000 refugees have entered the country from Syria across Jordan’s northern border. The figure comprises only those refugees who have crossed legally.
