Updated at 2:00 p.m. ET: As more Syrian rebels flooded into the country's capital, President Bashar Assad had reportedly left Damascus and was directing the response to the assassination of three top lieutenants on Thursday.
A day after a bombing killed his brother-in-law and two other key military figures, Assad was in the coastal city of Latakia, opposition sources and a Western diplomat told Reuters.
"Our information is that he is at his palace in Latakia and that he may have been there for days," said a senior opposition figure, who declined to be named, according to Reuters.
Latakia province is home to several towns inhabited by members of Assad's minority Alawite sect.
On Thursday evening, Syrian television showed Assad swearing in Brig. Gen. Fahed Jassim el Friej as defense minister, the president's first public appearance since the stunning bomb attack on a crisis meeting of defense and security chiefs.
U.S. State Department officials said Thursday afternoon they were not sure of Assad's location.
A diplomat, who is following events in Syria, told Reuters: "Everyone is looking now at how well Assad can maintain the command structure. The killings yesterday were a huge blow, but not fatal."
Meanwhile, rebel fighters streamed into Damascus convinced that they could take over the capital and isolate the government.
"Taking Damascus will be a morale blow to Assad's regime," Ali Bakran, a commander of a Free Syrian Army brigade that operates out Jabal al-Zawiya, told NBC News.
Rebels from his region has sent about 1,000 fighters to Damascus over the last two days, he said.
Bakran said that once the rebels had taken control of the capital, they planned seize state radio and television stations -- a huge symbolic and tactical victory for anti-Assad forces.
"Once we take over the TV and radio stations, the army will collapse," Bakran said.
'We will not stop'
And after Damascus, the rebels planned to march to Latakia, where Assad was reportedly staying, to "finish the job," Bakran added.
"We will continue our work, we will not stop, not after all this blood has been shed, not after all those innocents' deaths," he told NBC News.
Syrian rebels have kept up pressure following Wednesday's assassinations in Damascus, fighting loyalist troops within sight of the presidential palace and near government headquarters, residents said.
Residents said there was no let-up in the heaviest fighting -- now in its fifth day -- to hit the Syrian capital in a 16-month revolt against Assad, whose family has dominated the pivotal Arab country for 42 years.
The battles encroached within sight of the presidential palace, near the security headquarters where Wednesday's emergency meeting was held, with videos showing clouds of smoke rising over the skyline.
The U.N. Security Council put off a scheduled vote on a Syria resolution until Thursday and President Barack Obama telephoned President Vladimir Putin of Russia, Assad's main ally, to try to persuade Moscow to drop support for him.
Nevertheless, Russia and China vetoed the resolution threatening sanctions against Syria.
The bombing that killed Assad's brother-in-law, defense minister and a top general triggered fierce army retaliation with artillery unleashed on rebels massed in several districts and armed mostly with small arms and rocket-propelled grenades.
A video from overnight in Damascus' neighborhood of Sayed Zainab shows a makeshift clinic in a house, with blankets and medical supplies strewn all over the floor and a man shouting directions on a megaphone as men carry in mutilated bodies on sheets.
Some of the bodies were blackened, perhaps from a blast or a fire. Others were blown apart apparently by high explosive.
Residents in the Midan and Kafr Souseh districts reported constant blasts and heavy gunfire as helicopter gunships buzzed overhead.
"The shelling did not stop all night. Shelling could be heard in all the city. It was loud. There were also sounds of clashes. Not many people are venturing out. I can't even find a taxi, so I'm waiting for somebody to pick us up," a resident in Damascus told Reuters, speaking by telephone.
"Everyone in the neighborhood is arming themselves. Some with machineguns, some with shotguns. Some even just with knives. And whoever doesn't have anything just tries to stay awake and stay alert as much as they can," said another resident, speaking by phone from the Midan area.
"I can't even tell you what is going on outside because I've shuttered the windows and locked the doors. I just hear every now and then the gunfire, it's like it's in the room."
Many Damascenes were reported fleeing pockets of fighting.
"We've had a lot of people come in from last evening, from other neighborhoods like refugees, and people gather around them to hear what they've seen. My neighbor tries to see if they have relatives here or see if there is someone that can host them for a while," said a woman contacted by telephone.
Checkpoints around Midan and the ancient walled Old City of Damascus had been removed, residents said. It was unclear if security forces had changed tactics to stop rebels targeting soldiers, or if it was a temporary move in the heat of battle.
More world stories from NBC News:
- Experts say 'non' to Champagne as UK wines sparkle
- Mandela’s ‘Rainbow Nation’ determined to succeed
- Bombing kills Syrian ministers at heart of Assad rule
- North Korean leader 'awarded' top military rank
- US official: Up to $8 billion wasted rebuilding Iraq
- NBC's Ayman Mohyeldin answers your questions on Syria