Updated 7:55 PM ET
(AP) PARIS - U.S. Secretary of State Hillary Rodham Clinton called Thursday for the U.N. 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 U.S. wanted the "Friends of Syria" group to more actively consider contingency plans if the peace plan by U.N. and Arab League envoy Kofi Annan fell apart. Although U.S. policy has amounted to an acknowledgment that Assad is unlikely to be dislodged, the U.N. 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 U.N. Charter that would be militarily enforceable.
Any attempt to push for U.N. 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 U.N. 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, U.N. 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 U.N. 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 U.N. 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 U.N. ambassador Bashar Ja'afari had assured him "there will be full support, including air mobility."
Ban called the situation in Syria "highly precarious."
U.S. 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 U.N. Ambassador Vitaly Churkin said Moscow supports the expanded mission.