ST. PAUL  (AP) - A former state lawmaker is expected to become the first Republican to wage a 2012 challenge to Minnesota's popular Democratic U.S. Sen. Amy Klobuchar.

A political consultant with direct knowledge of the plans says Dan Severson will announce his candidacy Monday at the state Capitol.

The consultant spoke on the condition of anonymity because he wasn't authorized to discuss details ahead of the announcement. Severson declined comment.

The retired Navy pilot was the GOP's nominee for secretary of state last fall after serving in the state House for four terms, representing the St. Cloud area.

Klobuchar won her seat in a 2006 blowout. She's maintained strong public approval ratings throughout her term and had more than $2.5 million in campaign cash as of mid-April.

(Copyright 2011 by The Associated Press.  All Rights Reserved.)