UPDATE 1-Trump plans to nominate Jeffrey Rosen as deputy U.S. attorney general -senior official

President Donald Trump plans to nominate Jeffrey Rosen as the next deputy U.S. attorney general, a senior administration official said on Tuesday night. Rosen, currently deputy secretary of the U.S. Department of Transportation, would succeed Rod Rosenstein, who appointed a special counsel to investigate possible ties between Russia and President Donald Trump's campaign.

Rosenstein is expected to step down by mid-March, a Justice Department official said on Monday. Attorney General William Barr welcomed the choice of the new deputy, saying in a statement that Rosen had 35 years of experience at the highest levels of government and in the private sector.

"His years of outstanding legal and management experience make him an excellent choice to succeed Deputy Attorney General Rod Rosenstein, who has served the Department of Justice over many years with dedication and distinction," Barr said. Transportation Secretary Elaine Chao said Rosen had played a critical role in her department.

"I will be sorry to lose him, but I am confident that he is the right lawyer to help the new Attorney General succeed at the Justice Department, for the benefit of the American people," she said in a statement. Rosen's nomination must be confirmed by the U.S. Senate.

(Reporting by Steve Holland; Editing by Sandra Maler and Peter Cooney)