At least five people were killed Thursday in an attack by forces loyal to Yemen's outgoing President Ali Abdullah Saleh on the southern city of Taiz, the Yemeni news website Al-Masdar reported.
Fifteen were injured, some seriously, when the pro-Saleh troops shelled the city, the report quoted a medical source as saying, DPA reported.
Taiz has been a focal point of anti-Saleh protests that have gripped the impoverished Arabian peninsula country since February.
There was no immediate comment from the government on the report.
The shelling comes one week after Saleh and opposition leaders signed a Gulf-brokered deal on power transfer, effectively ending his 33-year rule.
A series of protests have, however, been held since then across Yemen against the deal for granting Saleh immunity from prosecution over allegedly ordering a deadly crackdown on his opponents.