WASHINGTON (AP) ― The Obama administration has pulled its ambassador home from Syria, arguing that his support for anti-Assad activists put him in grave danger ― the most dramatic action so far by the United States as it struggles to counter a Mideast autocrat who is withstanding pressure that has toppled neighboring dictators.

Syria responded quickly Monday, ordering home its envoy from Washington.

American Ambassador Robert Ford was temporarily recalled on Saturday after the U.S. received “credible threats against his personal safety in Syria,” the State Department said, pointing directly at President Bashar Assad’s government.

Ford, who already had been the subject of several incidents of intimidation, has enraged Syrian authorities with his forceful defense of anti-Assad demonstrations and his harsh critique of a government crackdown that has now claimed more than 3,000 lives.

Calling Ford back to the U.S. is short of a complete diplomatic break but represents the collapse of the administration’s hopes that it could draw Assad toward government changes and a productive role fostering Mideast peace. Washington held off on a full condemnation of Assad as his crackdown worsened this spring, and waited months to demand that he step aside.

Ford’s presence in Damascus had been an important symbolic part of President Barack Obama’s effort to engage Syria, which was without a U.S. ambassador for years after the Bush administration broke ties over Syria’s alleged role in the 2005 assassination of a political candidate in neighboring Lebanon.

With Moammar Gadhafi’s death last week in Libya, and the revolutions that toppled long-time leaders Hosni Mubarak in Egypt and Zine El-Abidine Ben Ali in Tunisia, Assad is among the Arab Spring autocrats left standing. Along with Ali Abdullah Saleh in Yemen, he is facing the most pressure from his citizens to leave power. Yet with his vast security network and close links with Russia and China, Assad is perhaps the one best placed to withstand pressures for change ― peaceful or violent.

In Washington, State Department spokeswoman Victoria Nuland said, “We are concerned about a campaign of regime-led incitement targeted personally at Ambassador Ford by the state-run media of the government of Syria.” She called on the Assad government to “end its smear campaign of malicious and deceitful propaganda.”

Nuland could not say when Ford might go back to Syria. Earlier, department spokesman Mark Toner said the U.S. Embassy would remain open in Damascus as the threats were specifically directed toward Ford, and that the ambassador’s return depended on a U.S. “assessment of Syrian regime-led incitement and the security situation on the ground.”

The State Department said there were no plans to expel Syria’s top diplomat in Washington in retaliation. But Roua Shurbaji, a Syrian Embassy spokeswoman, said Ambassador Imad Moustapha left the U.S. on Monday for consultations in Damascus. She said no other measure was being taken by the embassy, and declined to comment on the U.S. allegations.

Ford’s departure comes at a worrisome stage in the seven-month movement against Assad. U.S. officials are increasingly concerned about reports of weapons smuggling into Syria and the threat of peaceful protests being replaced by an armed uprising.

Amid that pressure, the world’s attention is turning to Syria, even if the demonstrations have delivered only a stalemate. The protesters are too weak to force Assad and his government from power, and for all its brutality the government cannot stamp out all opposition. At the same time, Assad’s pledges of reforms have long been ignored as meaningless and there is little indication his government is prepared to initiate a real dialogue with opponents.

If the level of violence resembles Libya’s before the NATO intervention, Syria is different because anti-government groups are insisting that they want no outside assistance. The opposition is also hindered in that it remains a largely Sunni movement, with Assad maintaining significant loyalty from his dominant Alawite sect and Syria’s minority Druze, Christians and business elite.

Ford arrived in January as the first American ambassador to Syria since the assassination of former Lebanese Prime Minister Rafik Hariri on a Beirut street. Syria at the time had thousands of troops in Lebanon and pulled many political strings there, but it has always denied any involvement in the bombing attack.

The Obama administration had hoped to persuade Syria to change its often anti-American policies regarding Israel, Lebanon and Iraq, and to drop its support for extremist groups. Syria is designated a “state sponsor of terrorism” by the State Department.

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 essentially dropped his engagement efforts and took on an increasingly high-profile role defending the rights of Syrian protesters.

That shift was cemented when Obama called on Assad to leave power in August.

“We believe Assad needs to step aside, so engagement with him is certainly over,” Nuland said on Monday. “But we are prepared to engage with Syrians of all stripes” and see “if they are able to take the next steps to pursue a democratic future.”