JEFFERSON CITY, Mo. (AP) — Missouri House Speaker John Diehl said Thursday that he is resigning from the Legislature after acknowledging that he exchanged sexually charged text messages with a college student serving as a Capitol intern.

Diehl said he is stepping down both from his House speaker's position and from his elected job as a Republican representative from suburban St. Louis. He said the resignation will take effect either Thursday or Friday, depending on when an orderly transition can be arranged.

Diehl acknowledged "making a serious error in judgment by sending the text messages" to the intern.

"I'm going to do what's best for the (House) body and the (Republican) caucus, and step aside out of my office," Diehl said in an interview with The Associated Press and reporters from three other media outlets.

"I made a mistake," Diehl said. "It's one that calls into question my ability to lead."

His resignation announcement came a day after The Kansas City Star released a story accompanied by screenshots of what the newspaper said were electronic messages between Diehl and the intern, who no longer works at the Capitol. Some of the messages were sexually suggestive.

Diehl, 49, is an attorney who lives with his wife and three sons in the St. Louis suburb of Town and Country. He first was elected in 2008 and had been chosen by colleagues as speaker in January to preside over one of the largest Republican legislative majorities in state history. He's known for his ability to work deals and to persuade rank-and-file members to stick together on the party's priorities.

Several Republican House members said they planned to meet as a caucus Thursday evening to discuss nominating a new speaker, who would have to be elected by the full House. Legislators face a 6 p.m. CDT Friday deadline to pass legislation this year.

Diehl's resignation adds to a tumultuous year in Missouri politics. In February, State Auditor Tom Schweich, who was seeking the Republican nomination for governor, fatally shot himself after alleging a top GOP official was leading a smear campaign against him. A month later, Schweich's spokesman also died in a suicide....