Syrian media and opposition activists say a car bomb has exploded in the central city of Homs, causing casualties.

The Syrian state-owned Al-Ikhbariya TV said the Saturday blast in the city's southern al-Nozah neighborhood was a suicide bomb. It reported casualties but did not give a number.

The Britain-based Syrian Observatory for Human Rights, which relies on a network of informants inside Syria, says the car was booby-trapped. It says seven people died, according to preliminary reports.

It was not immediately possible to reconcile the different accounts.

Activists say the al-Nozah district is populated largely by Alawites, members of the offshoot Shiite sect to which Syria's President Bashar Assad belongs.

Government troops are on an offensive against rebels near Homs, seizing a strategic town south of the city this week.