FRANKFORT, Ky. (AP) - Republican Secretary of State Trey Grayson says he has raised more than $600,000 since forming an exploratory committee to consider a run for U.S. Senate next year.

Grayson is the second potential GOP candidate to release fundraising totals for the second quarter. The other, Bowling Green physician Rand Paul, announced last week that he has raised more than $100,000.

Grayson and Paul are positioning themselves for a run if second-term GOP Sen. Jim Bunning pulls out of the race.

Bunning has left open the possibility that he may withdraw from the race if his own fundraising doesn't improve.

Bunning has said he will submit his contributions to the Federal Election Commission by the July 15 deadline for reporting.

(Copyright 2009 by The Associated Press. All Rights Reserved.)