Maj. Gen. Robert Mood of Norway will head the observer mission consisting of about 30 monitors, which will grow to 300 in the coming month, CNN reported.
"This is a matter of utmost urgency for the United Nations and all efforts are in place to make sure that we get the people on the ground as quickly as possible. ... Apart from Damascus, we have permanently based observers in Homs, Hama, Deraa and Idlib, so this process will continue," said Neeraj Singh, the observer team's spokesman.
Despite a cease-fire agreement put in place by the United Nations April 12 as part of a six-point peace plan, security forces continue to target civilians and opposition forces, said the Local Coordination Committees of Syria, a network of opposition activists.
At least six people died in Syria Sunday, the group said, including a father and son found dead in their Homs home.
The United Nations estimates about 9,000 people have died since March 2011 when the Syrian government began cracking down on demonstrations against President Bashar Assad's regime. Opposition groups put the death toll closer to 11,000. At least 700 people have been killed since the April 12 cease-fire, CNN reported.