WASHINGTON - President Barack Obama, speaking at the annual National Prayer Breakfast in Washington, took a moment to say he's praying for longtime U.S. Sen. Tom Coburn (R-Okla.).

Obama's comments about Coburn, who announced last month he was stepping down at the end of the session after another cancer diagnosis, came during remarks at the non-denominational gathering of political leaders on Thursday.

"And then there is one colleague of mine who is missing today. A great friend of mine who I came into the Senate with, Senator Tom Coburn. Tom is going through some tough times right now but I love him dearly even though we're from different parties. He's a little closer to Louie's political perspective than mine, but he is a good man, and I'm keeping him and his family in my prayers all the time. So just a shout-out to my good friend, Tom Coburn."

Coburn has been the U.S. Senate's most-prominent deficit hawk, bringing wasteful government spending to light. Coburn earned the nickname "Doctor No," for blocking bills he felt were unconstitutional.

He was elected to the U.S. Senate in 2004, and he previously served three terms in the U.S. House.