The U.S. closed its Syrian embassy and Britain recalled its ambassador to Damascus Monday in a dramatic new Western push to get President Bashar Assad to leave power as diplomatic efforts to resolve one of the deadliest conflicts of the Arab Spring collapsed.
The moves by the U.S. and Britain were a clear message that Western powers no longer see the point of engaging with Assad as they turn their attention to bolstering Syria's disparate and largely disorganized opposition to form a credible alternative to the current government.
"This is a doomed regime as well as a murdering regime," British Foreign Secretary William Hague told lawmakers as he recalled his country's ambassador from Syria for consultations on the escalating violence in the country.
"There is no way it can recover its credibility internationally," Hague said.
President Barack Obama said the Syrian leader's departure is only a matter of time, even as the Damascus regime intensified its assault on a revolt that has raged for nearly 11 months.
"The deteriorating security situation that led to the suspension of our diplomatic operations makes clear once more the dangerous path Assad has chosen and the regime's inability to fully control Syria," State Department spokeswoman Victoria Nuland said in a statement.
Robert Ford, the American ambassador, and 17 other U.S. officials left Syria and were expected to travel back to the United States. Ford informed Syrian authorities of the decision to leave earlier in the day, State Department officials said.
Even as the U.S. stepped up pressure on Assad to quit, Obama said a negotiated solution in Syria is possible and it should not be resolved by foreign military intervention.
There are fears that international intervention, akin to the NATO intervention that helped topple Libya's Moammar Gadhafi, could make the already combustible conflict in Syria even worse.
Syria is a highly unpredictable country, in part because of its web of allegiances to powerful forces including Lebanon's Hezbollah and close ally Iran.
The country also has multiple sectarian divisions, which the uprising has laid bare. Most of Syria's 22 million people are Sunni Muslim, but Assad and the ruling elite belong to the minority Alawite sect — something that has bred seething resentments.
The most serious violence Monday was reported in Homs, a city so battered that some opposition members have started calling it "the capital of the Syrian revolution." Several neighborhoods in the city, such as Baba Amr, are under the control of rebels.
Using tanks and machine guns, regime forces shelled a makeshift medical clinic and residential areas, killing a reported 40 people on the third day of a relentless assault on Homs, activists said. More than a dozen others were reported killed elsewhere.
Activists also reported a military offensive using tanks and armored vehicles in the mountain town of Zabadani, west of the capital Damascus.
The Homs offensive began Saturday, the same day Syria's allies in Russia and China vetoed a Western- and Arab-backed resolution aimed at trying to end the crackdown on dissent. That day, military forces killed up to 200 people in Homs — the highest death toll reported for a single day in the uprising — according to several activist groups.
There was no way to independently confirm the toll, and the Syrian regime denied it. The government says terrorists acting out a foreign conspiracy to destabilize the country are behind the uprising, not people seeking to transform the authoritarian regime.
Syria has blocked access to trouble spots in the country and prevented independent reporting, making it nearly impossible to verify accounts from either side as the conflict spirals out of control and turns increasingly bloody.
The violence has reinforced opposition fears that Assad will unleash even greater firepower to crush dissent now that protection from China and Russia against any U.N.-sanctioned action appears assured.
After the U.N. veto, the commander of the rebel Free Syrian Army, Col. Riad al-Asaad, said "there is no other road" except military action to topple Assad.
U.N. Ambassador Susan Rice says China and Russia are running the risk of suffering the same sort of international isolation as Assad because of their veto.
Moscow and Beijing "will come to regret" their votes, Rice told "CBS This Morning."
With diplomacy at an impasse, Secretary of State Hillary Rodham Clinton called Sunday for "friends of democratic Syria" to unite and rally against Assad's regime, previewing the possible formation of a group of like-minded nations to coordinate assistance to the Syrian opposition. Speaking in Bulgaria, she said the world had a duty to halt the violence and see Assad out of power. She called the U.N. setback a "travesty."
The contact group is likely to be similar, but not identical, to the one established last year for Libya, which oversaw the international help for Gadhafi's opponents. It also coordinated NATO military operations to protect Libyan civilians, something that is not envisioned in Syria.
As part of what was clearly a concerted Western effort, the Italian Foreign Ministry also said it summoned Syria's ambassador in Rome to express "the strongest condemnation and the indignation of the Italian government over the unacceptable acts of violence perpetrated by the regime of Damascus against the civilian population."
Already, more than 5,400 people have been killed since the uprising began in March, the U.N. said in January. Hundreds more are believe to have been killed since then, but the U.N. says the chaos in the country has made it impossible to cross-check the figures.
Syria has seen one of the bloodiest crackdowns since the wave of Arab uprisings began more than a year ago. Deaths in Egypt, Tunisia and Yemen have numbered in the hundreds. Libya's toll is unknown and likely higher than Syria's, but the conflict differed there: Early on it became an outright civil war between two armed sides.
Syria, in contrast, has developed into a murderous grind — although many fear it is swiftly developing into a civil war. Though internationally isolated, Assad appears to have a firm grip on power with the loyalty of most of the armed forces, which in the past months have moved from city to city to put down uprisings.
In each place, however, protests have resumed and now army defectors and others are taking up arms to fight back, adding to the bloodshed.
The Obama administration has long called on Assad to leave power, and officials insist his regime's demise is inevitable.
But just over a year ago, the administration had sought to engage Damascus and sent Ford to the country in the hopes of prying away Iran's main ally in the Arab world and gaining a more willing partner in American efforts to forge stability in Lebanon and peace among Israel and its Arab neighbors. Syria had gone years without an American ambassador after the Bush administration broke ties over Syria's alleged role in the 2005 assassination of politician Rafik Hariri in neighboring Lebanon, and it remains on a U.S. "state sponsor of terrorism" list.
Assad largely shrugged off U.S. attempts to pull his nation away from its alliances with Iran, Hamas and Hezbollah. And as protests escalated in Syria, Ford took on an increasingly high-profile role defending the rights of Syrian protesters. Threats led the U.S. to pull him out of the country in October, but he returned in December to what officials described as an important job monitoring abuses and developments on the ground.
On Monday, Obama defended his administration's actions during the 11-month uprising against Assad's regime.
"We have been relentless in sending a message that it is time for Assad to go," Obama said during an interview with NBC. "This is not going to be a matter of if, it's going to be a matter of when."