BEIRUT – Syrian rebels bombed a once luxurious, historic hotel being used as a government army base in the northern city of Aleppo on Thursday, levelling the building and causing multiple casualties in a giant explosion carried off by digging tunnels under the complex, activists and militants said.
The blast set off a gigantic mushroom cloud next to the historic citadel of Aleppo, collapsing the Carlton Hotel in a government-held area near the front lines in a the city, which has been one of the bloodiest and destructive battlegrounds of Syria's civil war.
The attack was a powerful show by rebels that they can still deal heavy blows at a time of a significant defeat elsewhere. Rebels on Thursday completed their withdrawal from Homs in a negotiated evacuation that surrenders Syria's third largest city to full government control for the first time in more than two years. Syrian state TV announced that the last of the rebels left Homs by the afternoon.
The death toll from the Aleppo bombing was not immediately known.
The Britain-based Syrian Observatory for Human Rights, which maintains a network of activists on the ground, said at least 14 soldiers were killed in the blast. The Islamic Front, Syria's biggest rebel alliance which claimed the attack, claimed to have killed 50 soldiers. Both groups did not say how they know how many soldiers died, and the claims could not be independently verified.
In a live broadcast from the site of blast, Syrian state TV's correspondent in Aleppo stood on a huge pile of rubble with twisted metal and palm trees sticking out, saying that the army had been using the building as a base and soldiers were positioned there at the time of the explosion.
The report did not mention casualties. The Syrian government does not publicize its casualties in the civil war.
The correspondent said the rebels blew up the building by tunneling underneath and planting explosives.
"They use tunnels like rats because they cannot face the Syrian Arab Army," the correspondent said, adding that the explosion felt like an earthquake to those around Aleppo.
The attack was the second carried out by the Islamic Front against the Carlton. The first, allegedly carried out also through explosives-packed tunnels, caused a partial collapse of the building in February. The Front, an alliance of several Islamic groups fighting to topple Assad, appears to favor this technique and has used it to carry out deadly attacks against government forces in Aleppo and Idlib provinces.
Thursday's explosion was much more powerful and sent an enormous mushroom of gray smoke into the sky and over the ancient city, according to a video posted online by activists. The video appeared genuine, matching Associated Press' reporting on the blast.
The explosion was a blow to President Bashar Assad's government in the north as his troops regained control of Homs under a cease-fire reached with rebels last week after a fierce, two-year battle with the rebels trying to oust him.
In the afternoon, a banner on Syrian TV said the last of the rebels left the city, proclaiming, "Old Homs is totally clean of armed terrorist groups" -- the term used by the government for the rebels. Homs Gov. Talal Barazi said earlier in the day that more than 1,500 fighters left the city since Wednesday. He said Homs will be declared a "secure" city once the army moves in later Thursday.
No such agreement appears to be in sight in Aleppo, Syria's largest city and former commercial hub. The city has been carved up into opposition- and government-held areas since the rebels launched an offensive there in mid-2012, capturing territory along Syria's northern border with Turkey.
In recent months, government aircraft relentlessly has bombed rebel-held areas of the city and the opposition fighters have hit back, firing mortars into government-held areas. The rebels also have detonated car bombs in residential areas, killing dozens of people.
The Islamic Front posted a statement on its official Twitter account Thursday saying that its "fighters this morning leveled the Carlton Hotel barracks in Old Aleppo and a number of buildings near it, killing 50 soldiers."
The Observatory said Islamic Front fighters planted a huge amount of explosives in a tunnel they dug below the hotel and detonated it remotely. It said the hotel was completely destroyed in the blast and at least 14 government soldiers were killed in the blast.
Syria's uprising began with largely peaceful protests and has evolved into a civil war with sectarian overtones, pitting largely Sunni Muslim rebels against Assad's government that is dominated by Alawites, a sect of Shiite Islam.
Islamic extremists, including foreign fighters and Syrian rebels who have taken up hard-line Al Qaeda-style ideologies, have played an increasingly prominent role among fighters, dampening the West's support for the rebellion to overthrow Assad.