Defense Secretary Leon Panetta vowed Friday to keep the US military the “strongest” in the world despite budget pressures, after being sworn in as the new Pentagon chief.

“As your leader, I will ensure that our nation continues to have the best-trained, best-equipped, and strongest military in the world — a force prepared to confront the challenges that face us,” Panetta wrote in his first message to troops after taking the oath of office at the Pentagon.