The United States has withdrawn its ambassador to Syria over concerns for his personal safety.

U.S. State Department spokesman Mark Toner said Monday the decision to return Ambassador Robert Ford to Washington was based solely on ensuring his safety after receiving “credible threats.” U.S. officials say Ambassador Ford left Syria over the past few days, and Toner said the U.S. cannot say at this point when the ambassador will return to the country.

Toner added the U.S. hopes the Syrian government will end what he called its “incitement campaign” against the ambassador.

Ford has angered Syrian authorities by speaking out against a government crackdown on protesters calling for President Bashar al-Assad to step down.

In July, the government issued an order restricting the movements of foreign ambassadors after Ford and the French ambassador to Syria visited the flashpoint city of Hama to show solidarity with residents there.

Last month, an angry mob confronted Ford as he prepared to meet a leading opposition figure in Damascus.

The United Nations says Mr. Assad's ongoing crackdown on dissent has killed more than 3,000 people. The government says terrorist gangs have killed hundreds of security personnel in the unrest.