Lt. Gov. Matt Denn says he will seek the seat of Delaware Attorney General Beau Biden following Biden's surprise announcement he will step down as attorney general to run for governor in 2016.

"My friend Beau Biden surprised all of Delaware, including me, by announcing that he would end his bid for re-election as our attorney general," wrote Denn in a letter announcing his candidacy as a Democrat for attorney general.

Having served two terms as lieutenant governor, Denn had been expected to run for governor in 2016. Since Biden's April 17 announcement, Denn said, many have urged him to run for attorney general. After talking with his family, Denn said, he decided to seek that position.

"I've realized that the attorney general's office would allow me to take a leadership role on some issues that are critical to our state," said Denn.

A replacement for Denn has not been announced. No Republicans have so far filed to run for attorney general, governor or lieutenant governor.

Primaries for statewide positions will be held Tuesday, Sept. 9.