BEIRUT: Dozens of civilians were killed on Wednesday as govern- ment troops pressed a relentless assault on the flashpoint central Syrian city of Homs into a fifth straight day, activists said. The Syrian Observatory for Human Rights said the deaths were caused by shelling and gunfire from Syrian forces, and added that three entire families were also killed overnight by regime-backed thugs. "Since dawn the shelling has been extremely intense and they are using rockets and mortars," said Omar Shaker, an activist in the besieged city reached by telephone from Beirut. He said the shelling was concentrated in the Baba Amr, Khaldiyeh, and Bayada neigh- bourhoods in an apparent bid to pave the way for a ground assault. The Britain-based Observatory has reported several hundred civilians killed since the onslaught on the protest hub was launched overnight Friday to Saturday.