CINCINNATI (AP) -- Ohio Sen. Rob Portman is calling Rep. Paul Ryan "a great choice" to be Mitt Romney's running mate for president, a designation many expected Portman to receive.

Portman said he has worked closely with Ryan, a Wisconsin congressman, and said Ryan is among his best friends in Washington. Republican presidential candidate Mitt Romney introduced Ryan as his vice presidential choice Saturday in Norfolk, Va., ending months of speculation. Portman was widely considered one of the top contenders for the vice presidential slot.

Portman called Ryan "an accomplished public servant and a leading voice on the most pressing issues facing our country." Portman said he will work hard to make sure the GOP ticket carries Ohio in November.