Former Rep. Gabrielle Giffords (D-Ariz.) has revealed she has regained movement in her right arm.

“This past year, I have achieved something big that I’ve not spoken of until now. Countless hours of physical therapy — and the talents of the medical community — have brought me new movement in my right arm,” Giffords wrote in an op-ed published in The New York Times Wednesday.

The announcement comes three years after the mass shooting in Tucson, Ariz., that left Giffords and 12 others wounded. Six people died. Giffords resigned from Congress in 2012.

The former congresswoman tweeted about her physical recovery on Wednesday and remembered those who were killed.

She is marking the anniversary by skydiving.

NBC’s “Today” show will air a story about Giffords’s leap on Thursday.

Last year, Giffords launched pro-gun control political action committee, Americans for Responsible Solutions, with her husband Mark Kelly.