Air strikes killed at least three civilians as Syrian government forces intensified their attacks and pressed forward with a new bid to retake several rebel-controlled districts of Homs.
A woman and her two children were reported killed in attacks on the Old City of Homs and the Khaldiyeh neighbourhood on Sunday, the Syrian Observator for Human Rights told the AFP news agency.
"Syrian warplanes carried out air strikes on the Old City... destroying a house and causing three deaths," said Rami Abdel Rahman, the director of the Syrian Observatory for Human Rights.
"Regime forces also carried out heavy shelling of the districts of Khaldiyeh and the Old City, and the sound of explosions could be heard."
"The army is continuing its attempt to enter Khaldiyeh, but it hasn't succeeded so far," he said.
Video uploaded to the internet also showed a man carrying an injured child from a destroyed building, asking members of the child's family if there were more people trapped inside. The origin of the video could not be verified.
Another video, said to have been filmed on Sunday, showed buildings coming under attack with explosions going off in the besieged district of Hama Road, in what a person off-camera described as 'barbaric shelling by Assad gangs," referring to the embattled president Bashar al-Assad.
The bombardment comes a day after the group said government forces were engaged in "unprecedented" bombardment of several parts of Homs, including Khaldiyeh, Bab Hud, Hamidiyeh and Bustan al-Diwan.
Al Jazeera's Charles Stratford said mobile phone connections in the city were cut on Saturday, before government jets began their bombing raids. Civilians were trapped in their homes in the attacks, he said.
An activist told Al Jazeera it was the most intense fighting the city had experienced, and that civilians face the "worst ever" if nothing was done to break the siege.
A spokesman for the Assad government said: "What's important is to cleanse those neighbourhoods of Homs that are in the hands of armed terrorists."