The United Nations suspended its monitoring mission in Syria on Saturday, a day after the chief observer there warned that spiraling bloodshed was hindering the ability of his team to fulfill its obligations.

Maj. General Robert Mood, the chief of the U.N. Supervision Mission in Syria, announced the suspension in a brief statement that cited the “significant risks” to the lives of the monitors posed by the escalating violence.

“In this high risk situation, UNSMIS is suspending its activities,” Mood said. “U.N . observers will not be conducting patrols and will stay in their locations until further notice.”

Mood said the suspension would be reviewed on a daily basis, and that the monitors would resume their activities “when we see the situation fit for us to carry out our mandated activities.”

But at a time when both sides in the conflict appear to be ramping up the violence, the prospects that conditions will improve soon appeared remote.

The collapse of the U.N. mission in Syria would effectively close the international community’s main window into the crisis in Syria and expose the United Nations to charges of abandoning civilians to slaughter. The demise of the monitoring effort would also increase pressure on the United States, Russia and other key powers to forge a new diplomatic strategy to contain a crisis that threatens to engulf the region.

“I have no doubt that we’re going to face a long and bloody summer,” said Salman Shaikh, a former U.N. official who serves as the director of the Brookings Doha Center. “By pulling these guys out, the international community will face a difficult choice: Is it going to get behind a much more coercive approach or is it going to allow the regime to kill hundreds if not thousands of civilians over the next few months?”

On Friday, Mood hinted that a suspension was possible when he warned reporters at a news conference in Damascus that it was becoming increasingly difficult for the 300-strong, unarmed observer mission to carry out its responsibilities.

“Violence, over the past 10 days, has been intensifying . . . willingly by the both parties, with losses on both sides and significant risks to our observers,” he said. “The escalating violence is now limiting our ability to observe, verify, report as well as assist in local dialogue and stability projects.”

In response to the heightened risks, Mood had already ordered the mission to scale back its patrols and other activities in Syria, according to two U.N. officials briefed on the decision.

Mood’s steps come as representatives of the more than 60 governments providing monitors to the U.N. mission have warned that the dangers faced by U.N. blue helmets might have grown too serious to justify their presence in Syria, particularly when the peace process is stalled.

On Wednesday, Brazil, India, Ireland and other countries with observers on the ground voiced anxiety about the security of their personnel. There is a “concern among the member states providing observers that the risk level is approaching the level where they are not willing to accept it any more,” Mood said.

Mood did not indicate at his news conference Friday whether he advocated beefing up the force or abolishing it altogether. But U.N. officials made it clear that they oppose expanding or reinforcing the U.N. mission, saying it would increase their exposure to attacks.

For the time being, no one has officially proposed pulling the observers out of Syria. But some Security Council diplomats have privately acknowledged that such a move would be likely in the event of a major attack that resulted in the death of significant numbers of U.N. personnel.

The U.N. monitoring mission is central to the implementation of a U.N.-mandated peace plan — known as Kofi Annan’s six-point plan — that has failed to halt the violence. An April 12 cease-fire brought only a brief respite, and many in the international community are warning that Syria’s 15-month-old uprising against the rule of President Bashar al-Assad is at risk of becoming an all-out civil war.

The observers’ role is to “monitor a cessation, not to stop, armed violence,” Mood said. But he said it is now clear that the plan is not being implemented either by the rebels or the government. “There appears to be a lack of willingness to seek a peaceful transition,” the general said. “Instead, there is a push towards advancing military positions.”

The monitors have provided a steady diet of raw information, however incomplete, linking the Syrian government and pro-government militias to some of the worst atrocities, including the massacre of 108 civilians in Houla, where the monitors said they found fresh tank tracks and evidence of government shelling.

The findings have largely undercut claims by Syria’s chief defenders, China and Russia, that Syrian government forces have played no role in mass killings, and secured their support for a Security Council statement condemning Syria for its role in the Houla massacre. The monitors have also documented multiple abuses by armed opposition groups and flagged concerns about the emergence of violent extremists groups in

“I think the mission has probably outperformed expectations,” said Richard Gowan, an expert on the United Nations at New York University’s Center for International Cooperation. “Its reporting has put the focus on
the government in a way that even independent media
and Syrian [nongovernmental organizations] could not, and made it harder for the Russians and Chinese to ignore the realities on the ground.”

But Gowan added that any hope that evidence of Syrian atrocities “would sway Russian opinion turns out to be a fallacy.”

Mood is scheduled to travel to New York to brief the Security Council on Monday. His dire assessment is likely to accelerate discussions underway in New York on the future of the U.N. mission in Syria. U.N. Secretary General Ban Ki-moon had already instructed his peacekeeping department to prepare a set of possible options for reconfiguring the peacekeeping mission when its 90-day mandate expires on July 20.

French Foreign Minister Laurent Fabius has proposed adopting a legally binding Security Council resolution that would compel Syria to implement Annan’s peace plan or face the “pain of very heavy sanctions.” But Russia and China would almost certainly block such a measure.

Susan E. Rice, the U.S. ambassador to the United Nations, meanwhile, has questioned the viability of the U.N. monitors. In a closed-door meeting this week, she likened them to “300 sitting ducks in a shooting gallery, one IED away from a disaster,” according to a diplomat who was present.

Lynch reported from New York.