Hawaii Sen. Daniel Akaka (D) announced Wednesday he will not run for reelection in 2012. 

The Honolulu Star-Advertiser reported that Akaka, 86, informed senior Hawaii Sen. Daniel Inouye (D) and his staff of his decision Wednesday evening. Akaka has served in the upper chamber since 1990.

"After months of thinking about my political future, I am announcing today that I have decided not to run for reelection in 2012," Akaka said, according to the Star-Advertiser. "As many of you can imagine, it was a very difficult decision for me. However, I feel that the end of this Congress is the right time for me to step aside."

“Senator Akaka has served this country with distinction for his entire adult life. All Americans are grateful for his service," Democratic Senatorial Campaign Committee Chairwoman Patty MurrayPatricia (Patty) Lynn MurraySenators press administration on mental health parity Top House, Senate Dems warn administration on short-term insurance Overnight Health Care: Opioid distributors summoned before Congress | Judge sets trial date in massive opioid lawsuit | Senators press DOJ to stop blocking medical marijuana MORE (D-Wash.) said. "He will be missed, but Democrats will absolutely keep his seat. With a heavily-leaning Democratic electorate and their native son up for re-election as President of the United States, we are confident the people of Hawaii will continue to have two Democrats serving them in the United States Senate.”

The senator's retirement creates another open seat for the Democrats to defend during the 2012 elections, which Republicans have targeted as an opportunity to take control of the Senate. 

“At the start of this election cycle, Senate Republicans expected to be on offense in a range of Republican-leaning states such as Montana, Missouri, and Nebraska. But the retirement of yet another longtime Democrat Senator further expands the map of takeover opportunities and further strengthens Republican hopes for a new Senate majority in 2012," National Republican Senatorial Committee spokesman Brian Walsh said. "With several strong candidates already looking at this race, even before Senator Akaka’s announcement, Hawaii presents an unexpected opportunity for Senate Republicans and we intend to make the most of it in 2012."

Akaka becomes the fifth member of the Senate Democratic Caucus who would have been up for reelection in 2012 to announce his retirement. Two Republicans up in 2012 have said they will not run for reelection.

The other Democrats set to retire are Sens. Kent Conrad (N.D.), Jeff Bingaman (N.M.) and Jim Webb (Va.). Independent Sen. Joe Lieberman (Conn.), who caucuses with Democrats, is also not running for reelection.

Former Rep. Ed Case (D) challenged Akaka in a 2006 primary race, and recent media reports have indicated that Akaka was struggling to fundraise.

Former Hawaii Gov. Linda Lingle (R) has said she is considering running for the seat. Potential Democratic candidates include Reps. Mazie HironoMazie Keiko HironoFormer Sen. Daniel Akaka of Hawaii dies at 93 Dems to top DOJ officials: Publicly promise not to interfere in Mueller's probe Zinke defends use of Japanese word: How could saying good morning 'be bad'? MORE and Colleen Hanabusa.

Akaka said he would serve out his term.

-- This post was updated at 7:52 p.m.