An interesting development for Senate-watchers, and not a welcome one for Sen. Mark Pryor:

Arkansas Republican Rep. Tom Cotton plans to announce his bid next week to challenge two-term incumbent Democratic Sen. Mark Pryor in next year’s elections, according to a person familiar with the congressman’s plans.

The person who spoke to The Associated Press on Wednesday was not authorized to speak publicly about the planned announcement and spoke on a condition of anonymity. But the freshman congressman has scheduled an event Tuesday with supporters in his hometown of Dardanelle.

Cotton’s entry will set up a heated and expensive fight for a U.S. Senate seat that Republicans believe is prime for a pickup in 2014, with groups on the right and left already waging a television ad fight in Arkansas. It also creates a domino effect, with several Republicans now eyeing Cotton’s seat in the U. S. House.

Cotton isn’t yet confirming, but his staff does confirm an event planned for Tuesday:

“On Tuesday Tom is inviting his hometown and all who have supported him along the way to hear about his fight to represent Arkansas’s values in D.C.,” said Cotton spokeswoman Caroline Rabbitt. “He looks forward to sharing his plans to continue that fight in the coming year.”

Cotton, an Iraq and Afghanistan veteran, was elected in 2012, handily defeating his Democratic opponent for a seat left open by the retirement of Rep. Mike Ross, who’s now running for governor. He boasts both hawkish foreign policy creds and fiscal conservative creds worthy of luring likely support from the Club for Growth, which has already been running ads against Pryor.

Arkansas is consistently ranked in the top Senate seats likely to flip in 2014:

Cotton, a military veteran with two Harvard degrees and a stint consulting for McKinsey & Co. under his belt, is a favorite of some Republicans, especially hawkish types, many of whom have been hoping he will run for Senate. He will face off against Pryor, a two-term conservative Democrat, in the deep-red state. When asked to confirm his Senate bid, his campaign offered details about a barbecue Cotton will hold next week at a community center in Dardanelle, Ark.

Cotton notably spoke last week in the House in opposition to the NSA surveillance bills.