Yemen's army and government both suffer from split loyalties to the new president, Abed Rabbo Mansour Hadi, and his predecessor, Ali Abdullah Saleh.
Monday's decision by Hadi transfers command of seven brigades of the Republican Guards to his direct oversight or control of regional units.
The Republican Guards, Yemen's best trained forces, are commanded by Ahmed Ali, son of the former president.
Hadi's move is expected to ease Saleh's influence over the military, which he used to challenge the new president.
Since Hadi took office in February, his forces have battled al-Qaida fighters who took over parts of the country's south last year.