The Obama administration said Monday that it had called home the U.S. ambassador to Syria over concerns about his personal safety, prompting Damascus to pull its ambassador from Washington and signaling a dramatic deterioration in the already tense U.S.-Syrian relationship.

State Department officials accused President Bashar al-Assad’s government of backing a campaign of political smear and intimidation against Ambassador Robert S. Ford, who has led U.S. criticism of the Syrian regime and whose meetings with activists and vivid Facebook postings have drawn the Damascus government’s ire.

Ford, a career diplomat, returned to the United States over the weekend and will remain there indefinitely until “the situation improves on the ground,” said Haynes Mahoney, the charge d’affaires at the embassy in Damascus. Hours later, the Syrian Embassy in Washington announced that its ambassador, Imad Moustapha, had been summoned back to Damascus for “consultations,” in what was clearly a retaliatory measure.

Mahoney said that no specific incident had prompted Ford’s abrupt departure Saturday but that the tone of several recent items in the government-controlled Syrian media had convinced officials that he could be in danger. Ford’s exit was kept under wraps until he was back in the United States, and Syrian officials said they had heard only that he was taking a weekend break in Amman, the Jordanian capital.

“The threats were really based on stories we saw that were very inciting, and we were concerned for his safety,” Mahoney said.

Ford’s return came amid increasing attempts in the West to tighten pressure on the Assad government over its brutal repression of the seven-month-old uprising in Syria. On Sunday, Sen. John McCain (R-Ariz.) became the latest U.S. politician to call for a Libya-style international military campaign to protect Syrians against government attacks. “The Assad regime should not consider that it can get away with mass murder,” McCain said at the World Economic Forum in Jordan.

State Department officials in Washington declined to comment on specific intelligence that led them to pull Ford out of Syria. But Victoria Nuland, spokeswoman for the department, said the Assad government was trying to “deflect attention inside the country away from the legitimate grievances of the peaceful protesters” by agitating against Ford and other foreigners.

U.S. officials cited an article in the government-run al-Thawra newspaper that accused Ford of working to provoke a civil war in Syria and another that accused him of running death squads while he was serving as a political officer in Iraq.

The State Department stressed that Ford had not been formally recalled, a step that would signal a rupture in diplomatic relations, and that he had been summoned home for consultations, with the presumption that he would return as soon as it was considered safe. Mahoney said the embassy, which has been operating on a skeleton staff since most nonessential officers were withdrawn earlier in the year, will continue to function.

“We hope that the Syrian government will stop this inciting because Ford was doing a very important job on the ground and giving significant support to the Syrian people,” Mahoney said.

Regime’s suffocating grip

Yet, although Ford’s departure will deprive the United States of eyes, ears and a powerful voice in Syria at a critical juncture in the uprising, in reality the climate in Damascus had become so oppressive that he and envoys from other nations had been increasingly hamstrung in what they could achieve, diplomats and activists in Damascus say.

“Ford’s movements around Syria have put the Assad regime’s human rights atrocities in the spotlight, something it cannot stand,” said Andrew Tabler, a Syria scholar at the Washington Institute for Near East Policy and author of “In the Lion’s Den,” a book about Syria under Assad.

Since Ford made a highly publicized journey to mingle with Syrian demonstrators in the then-protest epicenter of Hama in July, drawing the wrath of the regime, diplomats have been required to seek government permission to leave Damascus, which is not forthcoming.

So closely monitored are the activities and communications of activists that it had become too dangerous for them to meet with Western diplomats even in the capital, activists and diplomats say. And so frosty are relations between the United States and the Syrian government that encounters between their officials had ground almost to a halt, diplomats said.

A visit by Ford to the home of a dissident, Hassan Abdul-Azim, in September underlined the dangers. The building was surrounded by mobs of Assad supporters, who hurled tomatoes and eggs and trapped Ford inside for at least 90 minutes. In an earlier assault on a Damascus street, a government supporter hurled himself onto Ford before he was wrestled away by a bodyguard.

In July, the U.S. Embassy was attacked by stone-throwing government supporters, who broke windows, climbed onto the roof and raised the Syrian flag. The Obama administration said the attack was facilitated by Syrian security forces.

Syrians loyal to the government shrugged off Ford’s departure and said he will not be missed. “Ford left because his mission in Syria failed,” said Bassem Abu Abdullah, a professor of international affairs at Damascus University, who believes that Ford was instrumental in stirring up the protest movement.

However, he added, Damascus is confident that the United States will not dare permanently damage its relationship with Syria, which plays a strategically vital role in the Middle East because of its location. Syria is wedged between Israel, Iraq, Turkey and Lebanon.

“The U.S. government is not interested in closing diplomatic channels, and it didn’t do so for many years because they know the regime is strong and they have to deal with it,” he said.

‘Positive step’ by the U.S.

Despite the bravado, the move to summon Ford home represents a blow for the Syrian government, which had frequently cited his presence as evidence that the United States is not serious about its call for Assad to step down. Syria is facing growing international isolation, and sanctions imposed by the United States and the European Union are taking an increasingly heavy toll on the economy, even as there are signs that the scale of the anti-government demonstrations is waning.

Syrian activists calling for an end to four decades of Assad family rule said they hoped the U.S. move signaled an escalation of American pressure on the government. Though Ford’s attempts to connect with the protest movement made him popular among demonstrators, they say, there was a widespread sense among activists that his presence in Damascus constituted a subtle signal of continued U.S. support for the Assad government.

“This is a positive step by the U.S. government, and we hope it will be the beginning of something stronger,” said Omar al-Khani of the Syrian Revolution General Commission, a nationwide group that organizes protests, in the Damascus neighborhood of Qaboun. “It means the U.S. does not want to deal with this regime any longer.”

Warrick reported from Washington.