Sessions said Thursday he has the "highest confidence" in Deputy Attorney General Rod Rosenstein and described him as "highly capable."

A group of 11 House conservatives on Wednesday introduced articles of impeachment against Rosenstein, who oversees special counsel Robert Mueller's Russia investigation because Sessions has recused himself.

Sessions suggested lawmakers should instead focus on reforming the nation's immigration system.

He also expressed regret for having laughed at a "Lock Her Up" chant and repeated the words during a speech Tuesday at a high school leadership summit.

Sessions was in Boston Thursday to announce more than 20 arrests in a federal operation meant to crack down on identity theft and federal benefits fraud.