Updated

Three-term Sen. Jon Kyl announced Thursday he is retiring from Congress at the end of his term next year.

The Arizona lawmaker, the No. 2 Republican in the Senate, is the fifth senator scheduled for re-election next year to announce a departure from Congress when the 113th convenes in 2013.

"This is the time to end my public service, in January 2013, and therefore, I will not seek reelection to the U.S. Senate," said Kyl, who was speaking from Phoenix with his wife by his side.

He added it has been a "tremendous honor" to represent the people of Arizona, but "there comes a time when you have to consider other things."

Kyl said he's not going anywhere for the next 22 months, and will spend the remaining time in office focused on his job, and not a campaign, however, he would spend some of his time helping his allies and new Republicans get elected.

Saying that he wouldn't turn down an offer to run as a vice presidential candidate if a Republican presidential candidate thought he could be of service to the country, though he considered it a long shot, the senator nonetheless said it would be inappropriate to consider other job offers while still a member of Congress.

"That is the only office I would consider," he said later of the vice presidency, noting that he wouldn't want to be a Supreme Court justice. "I would not be a Cabinet secretary taking orders from some young (employee) in the White House."

Kyl, 68, served four terms in the House before winning a Senate seat. In 2006, he was named one of the 10 best senators by Time Magazine.

"He's leaving now at the top of his game, he has money in the bank, and he’s one of the few long-term incumbents who doesn’t face a Tea Party challenge," a senior Senate GOP aide with knowledge of Kyl’s decision said.

South Carolina Republican Sen. Lindsey Graham called the senator "one of the most dependable and solid leaders I have ever known."

"His decision to retire will be a great blow to the Republican Conference and Senate as a whole.  Jon is one of the smartest members of the Senate and knows how to get things done.  What he brings to the table will be very difficult to replace," Graham said.

Kyl has never lost an election, and would not have been expected to lose a vote for a fourth term. He will be 70 years old when he leaves. He joins Sens. Kay Bailey Hutchison, R-Texas, Jim Webb, D-Va., Joe Lieberman, D-Conn., and Kent Conrad, D-N.D., in the club of lawmakers who will find themselves less constrained in decision-making as a result of coming departure.

Replacing the senator, who is a major force in finance and defense policy, could prove to be an interesting fight.

Several officials, both GOP and Democratic, speculated Thursday that should Kyl resign, Rep. Gabby Giffords, rapidly recovering from a recent shot to the head at a constituent meeting, could be a contender. Other names mentioned are Homeland Security Secretary Janet Napolitano, who is also a former Democratic governor of Arizona; and Republican Rep. Jeff Flake, a rising conservative star and budget hawk.

Kyl said he hopes whoever runs to replace him would have the same conservative values as him and would "want to really fight for freedom for the American people from an oppressive government, which I say is a continuing challenge. I would hope that they believe strongly in national security issues, and could perhaps take up some of the issues I have led in national security, that they would work very, very hard, and always bear in mind that they work for the people of Arizona ... and finally that they would put everything in perspective, apply common sense, be honest and ethical, put their families and faith first and then their constituents here in Arizona."

Responding to the news, the Democratic Senatorial Campaign Committee said Arizona is now a "prime pick-up opportunity for Senate Democrats this cycle."

"Republicans now likely face a primary in Arizona, similar to impending free-for-alls in nearly every other state. Time after time, Republicans nominated unelectable candidates – and they look willing to do so again this cycle," said DSCC Communications Director Eric Schultz.