SAN FRANCISCO — After a long hiring freeze, the U.S. attorney’s office in the Bay Area will soon get an infusion of new blood.

U.S. Attorney Melinda Haag is in the process of hiring about a dozen assistant U.S. attorneys, an expansion of about 10 percent, lawyers with knowledge of the matter said. Spread across the criminal, civil, appellate and tax divisions, the new recruits will bring the office to the full 125 lawyers it has been allocated by the U.S. Department of Justice.