In a letter to Sen. Barbara Boxer (D-Calif.), released Monday, Hagel called the remark a “poor choice of words,” and vowed that he would work to “expand the depth and breadth of U.S.-Israel cooperation” if confirmed for the Pentagon’s top post.

“I regret saying it,” Hagel wrote. “I used that terminology only once, in an interview. I recognize that this kind of language can be construed as anti­-lsrael. I know the pro­-Israel lobby is comprised of both Jewish and non-Jewish Americans.”

Hagel, who has been tapped to replace departing Secretary Leon Panetta, has faced intense scrutiny over the past remark, where he accused a “Jewish lobby” of intimidating lawmakers. Pro-Israel groups and many GOP senators have seized on the comment, charging that Hagel would be a weak ally to Israel.