(CNN) Republican Sen. Rand Paul has five rib fractures, including three displaced fractures and bruised lungs, after an assault in his home in Bowling Green, Kentucky, a senior adviser told CNN.

"Displaced rib fractures can lead to life-threatening injuries such as: hemopneumothorax, pneumothorax, pneumonia, internal bleeding, laceration of internal organs and lung contusions," said Doug Stafford, the senior adviser, in a statement.

Paul sustained what were initially reported as "minor injuries" after a neighbor allegedly assaulted him in his home Friday. Kentucky State Troopers said the neighbor, Rene Albert Boucher, "intentionally assaulted" the senator. The motive for the alleged assault is unknown, but assaulting a member of Congress is a federal crime and could likely result in severe charges including felony assault or assault of a member. Both Capitol Police and the FBI are investigating the incident.

Boucher is currently facing 4th degree assault charges locally but those charges could be compounded with the federal charges.

Police say Boucher, 59, "admitted going onto Paul's property and tackling him."

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