WASILLA, Alaska (AP) — Alaska Gov. Sarah Palin surprised supporters Friday and announced she is resigning from office at the end of the month without explaining why she plans to step down — throwing into question whether she would seek a run for the White House in 2012.

The news rattles a Republican Party plagued with setbacks in recent weeks, including extramarital affairs disclosed by two other 2012 presidential prospects, Nevada Sen. John Ensign and South Carolina Gov. Mark Sanford.

Palin hastily called a news conference Friday morning at her home in suburban Wasilla, giving such short notice that only a few reporters actually made it to the announcement. Security blocked late-arriving media outside her home, and her spokesman, Dave Murrow, finally emerged to confirm that Palin will step down July 26. He refused to give details about the governor's future plans.

The former Republican vice presidential candidate said she had been considering leaving office since she decided not to run for re-election.

"Many just accept that lame duck status, and they hit that road. They draw a paycheck. They kind of milk it. And I'm not going to put Alaskans through that," Palin said.

Palin spokesman David Murrow said the governor didn't say anything to him about this being her "political finale." Murrow said he interpreted Palin's comment about working outside government as reflecting her current job only.

"She's looking forward to serving the public outside the governor's chair," he said.

Political analyst Larry Sabato, in Charlottesville, Va., said Palin's announcement left many wondering what her plans were.