Activists say Syrian troops have intensified their shelling of rebel-held neighborhoods in the central city of Homs as living conditions there deteriorate further.

The Britain-based Syrian Observatory for Human Rights and the Local Coordination Committees say the shelling killed at least one person on Sunday.

Activists say the city's besieged rebel-held areas have been under intense shelling and ground attacks for a week. The Observatory urged the U.N. to intervene and evacuate more than 1,000 Homs families, including women and children. It says their lives are in danger.

The latest shelling comes a day after U.N. observers suspended their patrols in Syria due to a recent spike in violence.

Activist say more than 14,000 people have been killed since the crisis in Syria began in March last year.