WASHINGTON, Sept. 22  The Bush administration plans to increase its 2008 financing request for military operations in Iraq, Afghanistan and elsewhere by almost $50 billion, with about a quarter of the additional money going toward armored trucks built to withstand roadside bombs, Pentagon officials said Saturday.

The increase would bring the amount the administration is seeking to finance the war effort through 2008 to almost $200 billion. Much of that money will go to refurbishment of military equipment and to the purchase of new protective equipment for troops, officials said, an indication of the toll that years of combat in Iraq and Afghanistan have taken on military vehicles, aircraft, weapons and other items.

Defense officials said earlier this year that the Pentagon would need a war budget of $141 billion in the fiscal year beginning Oct. 1. The additional request for nearly $50 billion, which was first reported in The Los Angeles Times on Saturday, will be presented by Defense Secretary Robert M. Gates during a Senate Appropriations Committee hearing on Wednesday, the Pentagon said. Deputy Secretary of State John D. Negroponte and senior military officials are also expected to attend the hearing.

Mr. Gates is to testify two weeks after Gen. David H. Petraeus, the top commander in Iraq, went before Congress to warn against a rapid reduction of troops in Iraq, and a week after a Democratic effort to limit troop rotations stumbled in the Senate. The financing request may serve to further sharpen partisan divisions over the Iraq war in general, and its soaring cost in particular.