More than 11,100 people have been killed in 13 months of unrest in Syria, including 55 since a UN-backed ceasefire took effect four days ago, a monitoring group said on Monday.
The death toll of 11,117 is 7,972 civilians and 3,145 military and gunmen, including fewer than 600 rebel fighters, the Syrian Observatory for Human Rights said.
Among the dead were nine civilians killed by regime forces on Monday, only hours after UN peacekeepers arrived in Syria to oversee a truce aimed at ending a year of bloodshed.
Security forces shot dead the two civilians when they opened fire on a car in the central city of Hama, said the Observatory, adding a third passenger died later of wounds.
Elsewhere, fierce gunfights broke out at dawn between forces loyal to President Bashar al-Assad and rebels in the northwestern city of Idlib, the Britain-based group said.
Four civilians were shot dead by security forces during the gunfight.
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In the same province, security forces killed a 16-year-old youth after it opened fire at random in the village of Khatab, said the Observatory.
Security forces also shot dead a civilian in the town of Inkhel, southern Daraa province, where the uprising against Assad's iron-fisted rule erupted in March 2011.
Meanwhile, regime forces shelled the rebel neighbourhoods of Khaldiyeh and Bayyada in the central city of Homs.
The Observatory said the areas were being targeted by mortars as the army attempted to seize control of the few old districts of the flashpoint city that remain held by rebels.
The security forces now control some 70 percent of Homs, which has seen some of the biggest losses of life of the 13-month uprising in Syria.
On Sunday, regime forces and pro-Assad gunmen killed nine civilians, bringing to 41 the number of people killed since Thursday, the day a UN-backed ceasefire entered into force.
The first batch of international observers tasked with monitoring the truce brokered by the UN-Arab League peace envoy Kofi Annan arrived Sunday in Syria, a UN spokesman said.
The six observers who arrived are the first of 30 monitors who were approved by the UN Security Council in a vote Saturday. The others are expected to arrive in coming days.