PARIS (AP) — US Secretary of State Hillary Rodham Clinton called Thursday for the UN Security Council to adopt an arms embargo and other tough measures against Syria to try to halt 13 months of bloodshed, but she acknowledged such diplomatic actions would likely be vetoed.

Clinton’s comments to Western and Arab diplomats from the so-called “Friends of Syria” group came as the head of the United Nations accused Syrian President Bashar Assad of failing to honor a peace plan that went into effect a week ago.

In a transcript of her remarks on the State Department’s website, Clinton stopped short of calling for outside military intervention in Syria — something there is little to no foreign appetite for — but said it was time to impose more consequential measures on Assad’s regime.

“We have to keep Assad off balance by leaving options on the table,” she told the gathering of 16 top diplomats.

Clinton’s address suggested the US wanted the “Friends of Syria” group to more actively consider contingency plans if the peace plan by UN and Arab League envoy Kofi Annan fell apart. Although US policy has amounted to an acknowledgment that Assad is unlikely to be dislodged, the UN resolution Clinton seeks could strengthen Syrian rebels fighting his regime.

“We need to start moving very vigorously in the Security Council for a Chapter 7 sanctions resolution, including travel, financial sanctions, an arms embargo, and the pressure that that will give us on the regime to push for compliance with Kofi Annan’s six-point plan,” Clinton said, referring to a resolution under the UN Charter that would be militarily enforceable.

Any attempt to push for UN sanctions on Syria would likely meet resistance from Syrian allies Russia and China, which hold vetoes in the Security Council. Moscow and Beijing have already twice shielded Syria from UN sanctions over Assad’s crackdown on a popular uprising that is estimated to have left 9,000 people dead and led refugees to pour into neighboring countries.

Clinton said she’d laid out the case for Security Council action earlier Thursday to Russian Foreign Minister Sergey Lavrov, whom she said “has recognized that we are not in a static situation but a deteriorating one.”

At the Paris meeting, French Foreign Minister Alain Juppe said the “Friends of Syria” group believes Annan’s plan is the “last chance” for Syria to avoid civil war. But he didn’t rule out the possibility of tougher action at the Security Council, including “in the direction that Madame Clinton indicated.”

The prospect of military action, however faint, remained in some minds in Paris. Foreign Minister Saad-Eddine El-Othmani of Morocco, whose country holds a Security Council seat, said: “We hope the Kofi Annan plan works to avoid this (possible) military intervention.”

Earlier, UN Secretary-General Ban Ki-moon said Syria was not honoring the cease-fire, which took effect last week, and that violence was escalating. Syrian activists said regime forces took control of a southern town and shot at activists in another soon after international observers left.

“Despite the government’s agreement to cease all violence, we still see deeply troubling evidence that it continues,” Ban said. “The past few days, in particular, have brought reports of renewed and escalating violence, including the shelling of civilian areas, grave abuses by government forces and attacks by armed groups.”

Ban also acknowledged “the increasingly difficult humanitarian situation within Syria and along its borders.” He said about 230,000 people had been displaced, and an estimated 1 million were in need.

Ban recommended the Security Council quickly approve a 300-member UN observer mission to Syria, a number larger than what was originally envisioned. But he said he will review ground developments before deciding when to deploy the mission. France’s Juppe said the mission should have “at least” 300-400 observers — though Assad’s government has indicated it won’t allow more than 250.

Ban said the mission’s success depends on Syria’s full cooperation and demanded that the regime ensure the observers have unrestricted freedom of movement, unfettered access to the Syrian people, and the use of helicopters and fixed-wing aircraft.

He said the UN and Syria signed “a preliminary protocol” in Damascus on Thursday but are still discussing the use of aircraft the nationalities of the observers. Ban said Syria’s UN ambassador Bashar Ja’afari had assured him “there will be full support, including air mobility.”

Ban called the situation in Syria “highly precarious.”

US Ambassador Susan Rice, the current Council president, said its members would have to send Ban’s recommendation for the expanded observer mission back to their capitals. Russian UN Ambassador Vitaly Churkin said Moscow supports the expanded mission.

Marina Ottaway, an analyst at the Carnegie Endowment for International Peace, a Washington think tank, said a failure of the cease-fire and the Annan plan would likely increase pressure on Russia to give some ground and allow limited action against Syria.

“I don’t think we are going to get Russia or China to agree to foreign intervention, but I think the present situation is going to make it very difficult for Russia to continue saying we have to try diplomacy, because the regime has shown once again that it has no intention of moving,” she said.

France, the US and others have repeatedly called for Assad to step down. But the Obama administration’s policy now reflects a consensus that Assad — with support from the military — has a strong hold on power and only an outside military strike could quickly oust him.

The evolving US position comes amid signs that rebel forces are poorly armed and disorganized, efforts to pay them by Arab Gulf states are failing, and sectarian divisions loom in Syria.

During testimony Thursday before the US Congress, US Defense Secretary Leon Panetta and Army Gen. Martin Dempsey, the chairman of the Joint Chiefs of Staff, outlined the steps the US and other countries are taking, including providing funding for emergency humanitarian assistance.

Dempsey said if called upon, the military would be ready to act and the services are working on ways to try to halt the violence. But both he and Panetta set a high threshold for US military involvement in the Middle East after the lengthy conflicts in Iraq and Afghanistan.

When pressed on the issue, Panetta said, “At this point in time… a decision is that we will not have any boots on the ground and that we will not act unilaterally in that part of the world.”

Much could depend on the role of Russia. In recent weeks, Russian leaders have sharpened their criticism of Assad, but have not given way on allowing any UN sanctions against Damascus.

El-Othmani, of Morocco, spoke in optimistic terms about the Kremlin’s position, saying he was “convinced that the Russians can participate in an effort to stop the violence.

“I was in Moscow yesterday, and spoke a long time with (Russian foreign minister) Lavrov,” El-Othmani said. “They have criticized the Friends of Syria — that’s his right — but the main thing is that he’s open, he supports the Annan plan and supports the observers’ mission.”

Only a small number of international observers are in Syria. On Thursday, they visited the southern province of Daraa, where activists said anti-regime protesters gathered around them in the village of Khirbet Ghazaleh. The state-run news agency confirmed the observers went to Daraa.

An amateur video posted online by activists showed at least two of the observers, including the team’s head, Col. Ahmed Himiche, standing outside a UN vehicle as dozens chanted, “Death is better than humiliation!” and “The people want to topple the regime!”

Troops also took control of the southern town of Busra al-Harir, which regime forces have been attacking for about a month, the Local Coordination Committees activist group said.

Adel al-Omari, an activist based near Busra al-Harir, said the whole town fell into the hands of regime forces Wednesday night after army defectors withdrew.

“Forty percent of Busra al-Harir’s homes are destroyed because of the shelling,” he said, adding that regime forces are detaining many in the town. “There is a lack of medical products, and regime forces have taken over makeshift hospitals.”

Al-Omari said that as observers were visiting the village of Hirak, hundreds of protesters chanted for the downfall of Assad’s regime. “Once the observers left, security forces started shooting to disperse the demonstration,” al-Omari said, adding that at least three protesters were wounded.

The Local Coordination Committees said troops opened fire in the Mahata area in the southern city of Daraa, apparently to impose a curfew. It said at least 10 civilians were wounded in the shooting.

Copyright 2012 The Associated Press.