Western and other nations are warning their citizens to leave Syria immediately, and have issued alerts not to travel there as the security situation continues to deteriorate in the face of President Bashar al-Assad's determination to defy not only the United Nations, but even his regional neighbors at the Arab League.

The U.S. Embassy in Damascus issued a heightened to alert to all American citizens who are still in the country to leave on any commercial flight that might still be available.

The message posted on the Internet, entitled, "Emergency Message for U.S. Citizens: Significant decrease in the number of commercial flights from Syria," was grim. It included a directive to Wardens that "Transmission by phone is mandatory."

Dated Wednesday, the message urged Americans in Syria to "depart immediately while commercial transportation is available. The number of airlines serving Syria has decreased significantly since the summer, while many of those airlines remaining have reduced their number of flights."

Americans were asked to enroll in the U.S. "Smart Traveler Enrollment Program (STEP), which makes it easier for the embassy/consulates to contact them in case of emergency, and for them to be in touch with the Bureau of Consular Affairs' Emergencies and Crisis.

Meanwhile, U.S. State Department spokeswoman Victoria Nuland announced Monday that Ambassador Robert Ford, who left the country last month amid concrete threats to his safety, will not be returning to Damascus this week, as previously announced. Ford is expected to return "by the end of the year," Nuland said. However, she cited several factors, including "events in Syria and the decision of other nations to bring their ambassadors home," as reasons to keep Ford Stateside for the time being. 

Turkey has also warned its citizens against traveling to Syria, and against staying anywhere in the country. In an address to Britain's Royal Society on Wednesday, Turkish President Abdullah Gul soberly told the audience that his Middle Eastern neighbor had reached the "point of no return." 

The Ankara government has warned its citizens returning from the Hajj pilgrimage to Mecca in Saudi Arabia not to travel overland through Syria to reach home as they traditionally do, but this year instead to travel by air. If such an option is really unavoidable, said the Turkish government, "journeys through Syria should be done during daylight hours" only.