Syrian rebels have claimed responsibility for blowing up an historic hotel that now serves as an army base in Aleppo.

The rebels perpetrated the attack by digging under the front line that divides the city, the Australian Broadcasting Corporation reports. The attack leveled the famous Carlton Citadel Hotel, which is across the street from the UNESCO-listed Citadel.

While state television did not report any casualties, the Syrian Observatory for Human Rights said there were dead and wounded government troops that were occupying the building.

"The explosion that was heard in Aleppo's Old City was caused by explosives planted by Islamist battalions in a tunnel beneath the Carlton hotel, which was occupied by regime troops," the group said.

The hotel, which opened shortly before the crisis began in 2011, is a renovated 19th century hospital building. The building was completely flattened by the bombing.

"Terrorists targeted the historic Carlton hotel in the Old City with a big explosion, destroying it completely and destroying several historic buildings nearby," state television said.

Rebels tried to blow up the hotel in February, but only caused minor damage. The hotel was one of the city's most sought-after hotels before the war due to its location and modern facilities.

In July 2012, rebels captured large portions of Aleppo, leaving the Citadel and nearby modern hotels, which once had many foreign tourists, directly in harms way.

Syrian forces say they now have full control over the city of Homs. Rebels held the Old City of Homs for almost two years. Currently, more than 900 rebel fighters made their way out of the "capital of the revolution" in convoys Wednesday.

The convoys were driven to rebel-held territory outside of Homs under a deal made between insurgents and President Bashar al-Assad's government forces.

Talal Barazi, Homs provincial governor, said 80 percent of the fighters have left the city, and the rest will be evacuated. He said the reconstruction of the city will begin after all of the rebels have left the city.

The loss of the city is a huge failure for the opposition, as it bolsters Assad weeks before his assumed re-election.

In 2011, thousands of Syrian citizens took to the streets of Homs to protest Assad's dictatorial government. Government forces cracked down on the city with ammunition and mortar bombs, leading the anti-Assad protestors to take up arms.

Rebel groups then took over cities, including Old City Aleppo, a year ago. Residents of the city said they starved.

After nearly three years of fighting, every building has bullet holes or parts that were partially destroyed by bombs. Many buildings, in addition to the hotel, have been leveled.

More than 150,000 people have died in the conflict so far, and millions have fled the country.