NASHVILLE (AP) - Kentucky's Rand Paul said Monday that he's "very supportive" of fellow U.S. Sen. Lamar Alexander but stopped short of endorsing the Tennessee Republican, who is up for re-election next year.

Alexander's campaign has been working to fend off potential primary challengers from the right. Tea party activists unhappy with Alexander staged a counter-rally last week when the senator held a campaign event in Smyrna. But a GOP opponent has yet to emerge.

Alexander's first TV ad of the campaign features Paul, a tea party favorite, in the two senators' role in halting an Army Corps of Engineers plan to erect barriers to prevent people from fishing below dams on the Cumberland River. The spot includes video of Paul saying: "Nobody wants to say no to Lamar Alexander."

Paul told reporters before a forum at a Nashville charter school on Monday that he didn't want to be drawn into what he called a media-driven "parlor game" about e ndorsements.

"I'm very supportive of Sen. Alexander, and I hope he doesn't get an opponent, I hope he wins re-election," Paul said. "I'm very supportive of him, but I really just don't want to get trapped into all these political games."

But Paul, who is considering a presidential bid in 2016, hasn't completely exempted himself from political endorsements in Tennessee. He was in in suburban Nashville on Sunday night to speak at a fundraiser for state Sen. Jack Johnson, R-Franklin.

Alexander said he was comfortable with Paul's position, noting that he has not been endorsed by any other U.S. senator other than Bob Corker, a fellow Tennessee Republican.

"We're not here to endorse each other," Alexander said. "What I try to do is earn the respect of my colleagues. And Rand Paul has certainly earned my respect for the way he speaks out and works on education, and I hope I can earn his.

"So we're not here about endorsements; we're here about how can we help teachers, and parents and children, and I appreciate very much what he has to say," he said.

Alexander said his campaign ad featuring Paul was not meant to give the impression that he had won his endorsement.

"My TV ad I hope gives the impression that we're pretty effective when it comes to defending the rights of fishermen," Alexander said.