BOWLING GREEN, Ky. — Sen. Rand Paul is recovering from five broken ribs and bruises to his lungs, and it is unclear when he will return to Washington, aides said Sunday, signaling that injuries he sustained Friday are far more severe than initially thought. 

The second-term Republican senator from Kentucky and 2016 presidential candidate was attacked, allegedly by a next-door neighbor, Rene Boucher, 59, who was charged with fourth-degree assault.

Paul made his first public comments since the incident on Sunday, tweeting that his wife "Kelley and I appreciate the overwhelming support after Friday's unfortunate event. Thank you for your thoughts and prayers."

[Suspect in attack on Sen. Rand Paul might face more serious charges, police say]

Doug Stafford, Paul's chief of staff, said in a statement Sunday that the senator has five rib fractures, including three displaced fractures, meaning the bones are partly or completely cracked. 

"This type of injury is caused by high velocity severe force. It is not clear exactly how soon he will return to work, as the pain is considerable as is the difficulty in getting around, including flying," Stafford said.