NICOSIA (AFP) - Syrian security forces shot dead 13 civilians on Monday and Tuesday in the central protest hub city of Homs, rights activist Rami Abdel Rahman told AFP. Thirteen civilians were killed yesterday and today in several parts of Homs when the army opened fire as it carried out an operation in the city to quash dissent, said the head of the London-based Syrian Observatory for Human Rights, reached by telephone from Nicosia. Late Monday another activist had said that security forces swept into the flashpoint central city and shot dead a civilian and wounded four others. Several coaches packed with security force personnel entered the Khalidiyeh neighbourhood of Homs and afterwards gunfire was heard, said Abdel Karim Rihawi. The wounded were taken to the Al-Bir Hospital, said Rihawi, who heads the Syrian League for the Defence of Human Rights. The shooting continued in more than one area of Homs. The atmosphere is tense. Security and pro-regime militias are invading the neighbourhood, shooting indiscriminately to terrorise people, pro-democracy activists wrote Tuesday on their Facebook page Syrian Revolution 2011, which has been driving force behind protests. A Homs resident, declining to be identified, said: Pro-regime (forces) attacked areas where the opposition lives. They sacked and looted shops. Fierce fighting rocked Homs at the weekend, with activists reporting that more than 30 people were killed in clashes between Christians, Sunni Muslims and Alawites from President Bashar al-Assads minority community.