Olympic swimming champ Michael Phelps banned for six months after DUI arrest
U.S. swimmer Michael Phelps competes on Aug. 24, 2014. By Patrick Hamilton for Agence France-Presse.

Michael Phelps, the 18-time Olympic swim champion arrested last week for drink driving, was banned for six months and dropped from the 2015 world championships roster Monday by USA Swimming.

The punishments came six days after Phelps was apprehended by police in his hometown of Baltimore and charged with driving under the influence of alcohol, excessive speed and crossing the center line while driving inside a tunnel.

On Sunday, Phelps said on Twitter that he would be taking a break from swimming and "take some time away to attend a program" for treatment of unspecified issues.