Annan said President Bashar al-Assad has still not fulfilled a promise to end violence
A handful of UN observers resumed their tour of Syrian hot spots on Wednesday as envoy Kofi Annan urged the fast deployment of the full, 300-strong mission and voiced alarm about persistent violence.
Nine civilians were reportedly killed across country, taking to nearly 300 the number of people who have died since a tenuous ceasefire went into effect on April 12.
Among them were four people whose bus was raked with gunfire by security forces at a checkpoint near Khan Sheikhun, a town in the restive northwestern province of Idlib, the Syrian Observatory for Human Rights said.
The Britain-based watchdog said two civilians were also killed by regime forces in the Harasta suburb of Damascus, while another was killed by sniper fire in Douma, a northeastern suburb of the capital.
One child died after being shot in a village in the eastern province of Deir Ezzor, according to the Observatory.
And regime forces also reportedly shot dead one citizen in the town of Rastan, in the central province of Homs.
Annan branded the bloodshed "unacceptable" as he and world powers called for the speedy deployment of the 300 observers, but a top UN official said it would take at least a month to get the first 100 in place.
Addressing the UN Security Council via teleconference, the UN-Arab League envoy said he was "concerned" about the violence surging after observers visit individual cities.
The former UN chief said Syrian President Bashar al-Assad has still not fulfilled a promise to end violence and said the situation was "bleak" and "unacceptable."
Annan said he was "particularly alarmed" at reports that government forces had entered the city of Hama after a visit by UN monitors and killed "a significant" number of people.
"If confirmed this is totally unacceptable and reprehensible," he told the council.
The Damascus-based Syrian League for Human Rights said nine activists were "summarily executed" by government forces in Hama on Monday, a day after they met UN observers in the central city.
More than 30 people were also killed in a government assault on Hama's Arbaeen neighbourhood on Monday, monitors have said, prompting anger and criticism by activists who questioned the use of the UN observer mission given the unending bloodshed.
Neeraj Singh, spokesman for an advance team of UN monitors who began arriving in the country on April 15 and are set to number 30 in the coming days, said the observers were conducting visits in various regions on a daily basis.
He said there were two observers based in the central town of Hama and two others in Homs, scene of fierce fighting between government forces and rebel troops. The rest of the team is based in Damascus.
Singh said the observers, who now number 15, reported back on a daily basis to Annan on what they witness.
"Whatever the observers see on the ground they are reporting to the joint special envoy Kofi Annan," he said. "It's not something that they discuss with the media."
Annan's spokesman Ahmad Fawzi acknowledged that the truce aimed at ending 13 months of violence that the United Nations says has killed more than 9,000 people remained "extremely fragile".
He said satellite imagery showed the regime had not fully withdrawn all of its heavy armour from population centres as required by the Annan plan.
Fawzi added that in areas visited by the observers, the guns were falling silent but credible reports indicated the violence resumes once they leave.
Given the ongoing violence, Annan said it was urgent for the 300 monitors to arrive in Syria quickly.
"We need eyes and ears on the ground, able to move freely and quickly, and to engage all parties -- something which must be guaranteed by the Syrian authorities," he said.
"Sustained pressure and engagement from the international community is essential."
But UN peacekeeping chief Herve Ladsous said it would take one month to get the first 100 of the 300-member force into Syria.
He told the Security Council Damascus was refusing to accept monitors from the Western and Arab coalition of countries in the so-called Friends of Syria group which has backed the Syrian opposition.