Sen. Pete Domenici will announce his retirement from the U.S. Senate Thursday after 35 years in office, sources familiar with New Mexico Republican's plans told the Journal's Washington bureau.

Domenici, the longest-serving senator in New Mexico history, will make his announcement tomorrow afternoon in Albuquerque.
   
Sources, who declined to be named publicly because they didn't want to preempt Domenici's announcement, said the overriding reason for the senator's decision to retire is his age and deteriorating health.
   
 Domenici will become the fourth Republican senator to bow out of office when their terms expire in 2008, which could give Democrats an opportunity to expand their majority in the 2008 elections. Sens. John Warner of Virginia, Chuck Hagel of Nebraska and Wayne Allard of Colorado have previously announced plans not to run again.

3:14 p.m. I have confirmed from two very reliable sources that Sen. Pete Domenici, who has served New Mexico for almost 35 years, will announce his retirement tomorrow in Albuquerque.

Domenici is headed to New Mexico now to make the announcement at 4 p.m. tomorrow afternoon at St. Mary's School in Albuquerque.

I've been hearing these rumors with more frequency in recent weeks but despite my frequent inquiries, Domenici's top staffers have denied any retirement plans. The senator's health has been in decline for years.

The Washington Post blog "The Fix" initially reported the news of Domenici's retirement late Wednesday afternoon.

Stay tuned. More to come.