The defection of a top general from the Syrian regime is "significant" and signals cracks in President Bashar al-Assad's inner circle, the Pentagon said Friday.
"We welcome this defection and we believe it is significant," Pentagon spokesman Captain John Kirby told reporters.
"He's a senior official in the Syrian army and a former friend of Assad, so we do believe this defection shouldn't be taken lightly," he said.
General Munaf Tlass defected three days ago, the highest-ranking military officer to have abandoned the Assad regime.
An officer in the elite Republican Guard charged with protecting the regime, he is the son of former defense minister Mustafa Tlass, a close friend of Assad's late father and predecessor, Hafez.
The United States hopes "others would follow his example," Kirby said. But he noted that it was too soon to say the regime's leadership was on the verge of collapse.
Assad "has loyalists still around him and certainly the vast majority of the Syrian military is still following his orders," the spokesman said.
But he hailed the defection as "a crack in that inner circle" because of the general's ties to the Assad family.
The head of the main opposition Syrian National Council welcomed the move as a major blow to Assad's rule.
Tlass was headed to Paris to join his wife and sister, Nahed Ojjeh, widow of Saudi millionaire arms dealer Akram Ojjeh, a source close to the regime told AFP.
France, hosting a meeting of about 100 countries from the so-called Friends of Syria group on Friday, confirmed the defection.
Tlass's move comes two weeks after a colonel in the privileged Syrian air force won political asylum after landing his MiG-21 fighter in neighboring Jordan.
According to the source with close ties to Damascus, Tlass undertook several unsuccessful reconciliation missions between regime loyalists and rebels in Rastan and the southern province of Daraa.
Months later, he gave up his military uniform and opted for civilian clothing. He set up residence in Damascus, where he let his beard and hair grow long.
Another source in Damascus told AFP that Tlass's relations with the authorities became irreconcilable after the regime's fierce assault on the Homs district of Baba Amr in February that cost hundreds of lives.