Senior military figures who are part of President Bashar Assad's inner circle are among those understood to be preparing "exit strategies" if the Syrian regime becomes critically threatened by the rebellion, the U.S. officials told the British newspaper The Daily Telegraph.
The close Assad advisers are establishing lines of communication with rebel leaders to discuss how they would be received if they deserted, the officials said.
The aides are also contacting Western governments, they said.
"We are seeing members of Bashar Assad's inner circle make plans to leave," a senior U.S. official in Washington told the newspaper.
The secret preparations include moving large sums of money offshore into Lebanese and Chinese banks, the Telegraph said.
Syrian opposition groups confirmed they were actively courting U.S. help to encourage more defections.
"I know for sure there are some high-ranking officers who are waiting for the right chance to defect," a senior opposition source told the newspaper.
"We have names of people in the presidential palace. There are rumors that there is one who is really close to the president and we are expecting to see him out of the country soon," the source said.
Neither the White House nor the State Department had an immediate comment.
The State Department did respond to Thursday's defection by a Syrian air force colonel who abandoned a mission to attack the city of Daraa -- the starting point of the 16-month-old uprising against the Assad regime -- and instead landed his MiG-21 supersonic jet fighter at King Hussein Air Base in Mafraq, 50 miles north of Amman.
Jordan's council of ministers approved Col. Hassan Merei al-Hamade's asylum request within 6 hours, officials said.
Syria's Defense Ministry called Hamade "a deserter and a traitor to his country, and to his military honor, and he will be sanctioned under military rules," Syrian state TV reported.
A source close to the opposition told the Los Angeles Times the pilot was a father of five from restive Idlib province and said his family was under the protection of the Free Syrian Army, a rebel umbrella group based in Turkey that includes many deserters.
State Department spokeswoman Victoria Nuland called Hamade's defection "extremely courageous and the right kind of move."
She said the Obama administration wanted "to see more of this."
"We're continuing to watch this. I mean, it's obviously a significant moment when a guy takes a $25 million plane and flies to another country and asks for asylum," Nuland said in Washington. "This is how these things start."
Opposition groups said they hoped Hamade's defection could lead to an exodus.
They also alleged the Assad regime managed to prevent widespread defections with a carefully orchestrated blackmail campaign -- threatening families of diplomats and high-level figures to keep them loyal.
More than 100 civilians were killed in clashes across Syria Thursday, the Syrian Observatory for Human Rights said.
More than 50 regime soldiers and 10 rebel fighters were also killed the rights group said.
In Daraa, which Hamade was supposed to have attacked, two children were among 24 civilians and five rebels killed, the group said.
Meanwhile, Moscow is preparing to evacuate Russian nationals from Syria, Moscow business daily Vedomosti reported.
No orders have been made, but plans are in the works in case tensions escalate or outside powers intervene, the newspaper said, citing security services sources.
The Defense Ministry, Emergency Situations Ministry and other government agencies are involved in the plans, the sources said.