UNITED NATIONS - Secretary General Ban Ki-moon, concerned about a faltering UN-backed cease-fire in Syria, has recommended that the Security Council approve an initial contingent of 300 UN unarmed military observers to monitor the truce.

In a letter to the 15-member council, the UN chief proposed that it establish a full-fledged UN monitoring mission of “blue berets” backed by air transport, with the authority to carry out unimpeded investigations into possible cease-fire violations by the Syrian government or armed opposition.

The violence in Syria has persisted, albeit at a reduced level, despite a six-point peace plan including a cease-fire negotiated by former UN secretary general Kofi Annan, acting as a special UN-Arab League envoy. Annan’s blueprint included deployment of a UN observer force to quell the bloodletting that has killed an estimated 9,000 people over the last 13 months and driven half a million from their homes.

An initial 30-member observer team has arrived and reached agreement with Assad’s government on how it will “monitor and support a cessation of armed violence in all its forms by all parties,” according to Annan’s spokesman, Ahmed Fawzi, who issued a statement in Geneva.

Ban’s letter to the Security Council said the proposed new UN observer mission, to be called the UN Supervision Mission in Syria (UNMIS),would be deployed within weeks after the council adopted a resolution creating it. Ban suggested that the mission might need to be enlarged and that he would come back to the council within 90 days with a new plan to “further develop and define the mission’s mandate, scope and methods of work.”

“It would be a nimble presence that would constantly and rapidly observe, establish and assess the facts and conditions on the ground in an objective manner, and engage all relevant parties,” Ban wrote of the new mission. His eight-page letter was distributed to the Security Council late Wednesday. Security Council diplomats said they hope a resolution can be voted on by early next week.

The letter provides a mixed account of the security conditions on the ground since the United Nations deployed its first monitors three days ago in Syria, noting that “it remains a challenge to assess accurately unconfirmed and conflicting reports of developments in Syria.”

Ban wrote that “levels of violence dropped markedly” in Syria since April 12, when a UN-brokered cease-fire went into effect. However, he added, “the Syrian government has yet to fully implement its initial obligations regarding the actions and deployments of its troops and heavy weapons, or to return them to barracks. Violent incidents and reports of casualties have escalated again in recent days, with reports of shelling of civilian areas and abuses by government forces. The government reports violent actions by armed groups. The cessation of armed violence in all its forms is therefore clearly incomplete.”

In Syria, according to the UN, both government forces and the opposition have violated conditions of Annan’s plan, and dozens of people have died in the last week.

At least four people were killed in violence across Syria even as authorities in Damascus penned an agreement aimed at putting a stop to 13 months of bloodshed, a monitoring group said.

One civilian was killed during an assault by government forces in the northeastern oil city of Deir Ezzor and three others died from gunfire in the town of Yabrud, north of Damascus, the Syrian Observatory for Human Rights said.

The casualties brought to 124 the number of civilians who have died since a UN-brokered ceasefire went into effect in Syria a week ago on April 12, said Rami Abdel Rahman, head of the Britain-based watchdog.

Three civilians were also wounded on Thursday in the assault on Deir Ezzor where fighting was raging between government troop and rebel fighters, the group said.

It also reported clashes in Daraa, south of Damascus, cradle of the 13-month uprising against the regime of President Bashar al-Assad, and shelling in the flashpoint central province of Homs.