UN leader Ban Ki-moon urged the UN Security Council on Friday to reduce the number of unarmed military observers in Syria and put more stress on political efforts to end the conflict.
Ban recommends in a report that the mission in Syria with a "reduced military observer component" be redeployed to the capital Damascus, from regional cities where the conflict has grown in recent weeks.
The divided Security Council must make a decision on the future of the 300 unarmed military observers and more than 120 civilian staff in Syria by July 20.
Tension in the debate on the future of the UN Supervision Mission in Syria is likely to increase in the wake of western calls for sanctions against President Bashar al-Assad despite the opposition of veto-wielding council members Russia and China.
The UN leader expressed alarm at the "dangerous trajectory of the conflict and the destructive dynamics at play" between the government and opposition.
He said the UNSMIS mandate should remain unchanged, though with the focus shifting from monitoring a ceasefire that has never taken hold toward a more political role.
"If UNSMIS were re-oriented in this manner, the mission would redeploy from the field to the capital to minimize risks, retaining core civilian and military observer capacities to focus on the spectrum of initiatives feeding into the political process," said the report.
Ban and UN-Arab League envoy Kofi Annan want the mission to deal more with efforts to persuade the government and opposition to halt the violence, which activists say have left more than 16,500 dead in the past 16 months.
"From a central hub in Damascus, the civilian component would continue liaison and dialogue with opposition and government representatives in the provinces as security conditions allow."
"A reduced military observer component would support these civilian-led activities with military liaison and, as it does now, conduct visits to incident sites," said the report.
UNSMIS was sent to Syria in April with an initial 90-day mission to support a peace plan that Annan agreed with Assad, but was never implemented.
The United States said when the mission was approved that it could not rule out blocking an extension. According to UN officials, several of the approximately 50 countries that provided observers have expressed fears about their safety and indicated they could withdraw them.
UNSMIS suspended its patrols on June 15 and this week, chief Major General Robert Mood announced that he was closing observer offices in Hama, Idlib and Tartus, in a move to retrench to regional offices.
Mood has also ordered a first temporary reduction in the number of observers.
Ban said the spiraling violence now exceeds levels that preceded Assad's agreement to cease hostilities.
He warned that if the security and political conditions in Syria become "untenable," the UN would have to consider closing the mission.
Shutting down UNSMIS was one of the options under consideration, Ban said, warning this would "signal a loss of confidence" in the ability of the international community to influence events.
The UN chief said he had also considered expanding the number of military observers or adding armed guards to protect them. But Ban doubted that Assad's government would agree to either option.
"The risk of exposure would increase in tandem with expansion, as well as unrealistic expectations of UNSMIS protective and intervention capacities," said the report.
The UN observers say they have already faced hostility from some Syrian groups because they have not halted violence since they were deployed.
A debate on Ban's report will officially start at a meeting Wednesday in which Annan is expected to brief representatives. A vote on the future of UNSMIS has been slated for July 18.