"Ten people were killed and 22 wounded in a car bomb attack on a collective taxi stand in Zahraa," a district inhabited by Alawites, the Shiite sect of President Bashar al-Assad, Talal al-Barazi told AFP.
Barazi had earlier reported a toll of eight, while the Syrian Observatory for Human Rights gave a death toll of 12.
A second car bomb exploded in another district of the city, wounding three people but without causing more deaths, said Barazi.
Homs has seen some of the worst violence in Syria's more than three-year-old civil war.
For almost two years, anti-regime fighters and local residents were trapped in a suffocating army siege of the Old City in the heart of Homs.
They were evacuated earlier this month under an unprecedented deal involving a major rebel coalition and Iran, a strong backer of the regime.
The end of the Old City siege brought it back under regime control, leaving only the Waer district in northwest Homs in rebel hands.
The Observatory and activists say a deal is being negotiated for a truce in Waer, which is home to hundreds of thousands of civilians.