Longtime Santa Clarita Valley Rep. Howard “Buck” McKeon, who under House rules is serving his last of three terms as chairman of the powerful House Armed Services Committee, is expected to announce Thursday at 9 a.m. in Washington (6 a.m. in California) that he will retire at the end of his current term.

Sources close to McKeon confirmed Wednesday that he will not seek re-election.

An email from McKeon spokeswoman Alissa McCurley announced an on-camera statement by McKeon in the House Armed Services Committee hearing room.

State Sen. Steve Knight, R-Palmdale, who also represents northern and eastern portions of the Santa Clarita Valley, said he received word of the announcement Wednesday morning in a news release from a public relations firm that works with McKeon.

Knight’s confirmation comes on the heels of numerous Washington, D.C.-based blogs that have been reporting his retirement.

Rumors have been rampant that McKeon, who will be termed out as chairman of the powerful House Armed Services Committee in November, has been planning to retire.

Two Republicans, Tony Strickland and state Sen. Steve Knight, R-Palmdale, have already announced their intentions to run, should McKeon retire, which all but confirmed the speculation for many.

Asides from the two Republicans, in the historically Republican district, there are several candidates seeking the 25th Congressional District seat.

Jorge Ricardo Puentes, an Army veteran; Lee Rogers, a podiatrist; and Evan “Ivan” Thomas, a retired Air Force pilot, have all announced their intentions to run.

McKeon garnered slightly less than 55 percent of the vote in his last race against Rogers in November 2012.

Strickland has already filed paperwork to run for the 25th Congressional District; Knight said he would wait until the announcement was made official, out of respect for McKeon.

“I’ve known Buck for a very long time,” Knight said. “I appreciate his service to the House of Representative.”

Knight praised the way McKeon has served the citizens of Santa Clarita, Antelope and Simi valleys.

“This is my district,” Knight said, of his impending plans to file.

However, the door is now open for what is expected to be a highly competitive race in November.

“The demography is changing, and people’s ideologies are changing, as well,” Rogers said. “I think that you’re going to see a really large effort by both parties to try to win this seat.”

Rogers said the open seat is a big advantage for him, because the 25th Congressional District seat is “not really a Republican district anymore.”

“Our country, I think, is going in the wrong direction,” Rogers said. “We need people who are going to go to Washington (D.C.) and solve problems.”

Right now, the 25th Congressional District seat is one of 14 out of 435 that will be open, Rogers said, adding that he anticipated a highly scrutinized race that the Democratic Party feels it can win.

“This is my home, this is where my allegiance is. I want to see that we can do for this district that will help us in job creation and in moving this district forward, and to help the three valleys with the major industries out here,” he said, mentioning pharmaceuticals, aerospace and filming.

“I want to make sure that the future is bright for our three valleys,” he said.

Strickland said he would hold off comment until the official announcement was made when reached by phone Wednesday.

“He just made the decision that it was time (to file papers to run) to give both districts some clarity,” said Jeff Burton, a campaign spokesman for Strickland.

The move was more out of respect for Jeff Gorrell, whom he identified as Strickland’s friend, Burton said, in an interview shortly after Strickland filed his paperwork.

Rep. Mac Thornberry (R-Tex.) is considered the favorite to succeed McKeon as chairman of the Armed Services Committee, according to a Washington Post report.

A Santa Clarita Valley official said he’s received word on the retirement of Congressman Howard Buck McKeon, R-Santa Clarita.