- Six monitors will begin work Monday, a spokesman says; 24 more are expected soon
- At least 23 people died across Syria on Sunday, opposition activists say
- Regime official: Syria must coordinate "all the steps on the ground" for U.N. observers
- The government and the opposition trade blame for violating a cease-fire
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(CNN) -- The first members of a U.N. observer team will begin their work in Syria on Monday, tasked with monitoring a tenuous cease-fire that is showing signs of collapse.
"They will be liaising with the Syrian government, security forces and the opposition members to establish the monitoring process across the country," said Kieran Dwyer, a spokesman for peacekeeping missions at the United Nations.
The initial group of six observers arrived in Damascus on Sunday, a day after the U.N. Security Council voted unanimously to authorize unarmed observers to travel to Syria to monitor the cease-fire -- part of a peace plan brokered by U.N.-Arab League special envoy Kofi Annan.
The Security Council approved the deployment of an advance team of 30 monitors meant to pave the way for a larger group of up to 250 observers and called on Syria to provide them unimpeded freedom of movement. The remaining 24 members of the advance team will arrive in Damascus in the coming days, Dwyer said.
The second, larger deployment is contingent on how the cease-fire holds and whether discussions between Syria and Annan can make headway to quell the bloodshed.
But since the deadline for the cease-fire passed on Thursday morning, reports of deadly violence at the hands of the regime continued.
At least 23 people died across Syria on Sunday, including 11 in the besieged city of Homs, opposition activists said.
Government helicopters pummeled Homs from the sky, said the Local Coordination Committees of Syria, a network of opposition activists.
"One bomb is being shelled every 10 minutes from the military academy, aiming at al-Wair neighborhood in Homs," the group said Sunday morning. Homs has been a bastion of anti-government sentiment.
But the state-run Syrian Arab News Agency blamed "armed terrorists" for violating the cease-fire, quoting an unnamed military official's assessment that the groups "have hysterically escalated their aggressions on the army, the law enforcement forces and the civilians."
The Syrian regime has consistently blamed the violence in the country on such groups, but many world leaders have said the government is lethally cracking down on dissidents seeking democracy and an ouster of President Bashar al-Assad, whose family has ruled Syria for 42 years.
CNN cannot independently verify reports of violence and deaths, as the government has severely restricted access by international media.
The U.N. Security Council's resolution to send monitors was the group's first on Syria since the crisis in the country broke out more than a year ago.
U.N. Secretary-General Ban Ki-moon pledged to try to develop by Wednesday a more concrete proposal for an official, and likely more broadly defined, observer mission.
Bouthaina Shaaban, a Syrian government spokeswoman and presidential adviser, said Sunday that the "length of work of the observers and their movement will be determined in coordination with the government of Syria." A protocol agreement on the observers' mission will need to be signed before the larger group is allowed to come, she said, according to state-run Al Dunya TV.
"Syria cannot be responsible for their security unless it participates and coordinates all the steps on the ground," she said.
U.S. Ambassador to the U.N. Susan Rice welcomed Saturday's long-awaited resolution, but said the United States was "under no illusions" about its immediate effect.
Rice, the current Security Council president, pointed to reports of ongoing violence, which are already "raising renewed doubts about the sincerity" of Syrian authorities to end hostilities.
Renewed shelling on Homs over the weekend "absolutely" constituted a violation of the current cease-fire, she said.
While the council's decision "does not satisfy us fully," Syria "will be on board" with the resolution, Syria's U.N. ambassador Bashar Jaafari said.
Jaafari also called for a lifting of sanctions, blaming them for costing his country "billions of dollars."
On Saturday, British Ambassador to the U.N. Mark Lyall Grant said the United Kingdom welcomes the resolution, but regrets "that it comes only after the Syrian people have for over one year suffered unimaginable brutality at the hands of a regime that has prioritized its own survival over the needs, rights and aspirations of the people it should serve and protect."
The United Nations estimates at least 9,000 people have died since the protests began, while others put the death toll at more than 11,000.
CNN's Yousuf Basil, Saad Abedine, Richard Roth, Salma Abdelaziz and Elise Labott contributed to this report.
