DOHA, Qatar, Feb 14, 2012 (IPS/Al Jazeera) - Syrian troops have shelled the central city of Homs for a 10th day, opposition activists say, amid suggestions by the U.N.'s human rights chief that the U.N. Security Council's failure to pass a resolution condemning Syria has encouraged the government to intensify its attacks on civilians.

At least seven people were killed and more than 20 injured on Tuesday in the city's Bab Amr neighbourhood, which endured relentless barrage of heavy machinegun fire, tank shells, mortars and rocket-propelled grenades, according to the activists.

Speaking to Al Jazeera from Homs, activist Hadi al-Abdallah told Al Jazeera that the shelling, which started at 5:30am local time, was the heaviest in days.

"Bab Amr and adjacent Inshaat neighbourhoods are being shelled every 15 minutes," he said.

"We do not know what to do with the injured. Since the assault started 10 days ago, there have been more than 1,000 people injured."

Bab Amr is an opposition stronghold that government forces have been struggling to regain control of.