The chief of naval operations, Adm. Michael G. Mullen, also counseled a cautious buildup to the higher rate of production by the team that builds Virginia-class submarines, the Electric Boat Division of General Dynamics, based in Groton, and Northrup-Grumman's Newport News Shipbuilding in Virginia.

``We need support for sustained funding of our shipbuilding account,'' both to keep the shipbuilders healthy and to start rebuilding a submarine fleet that, like the Navy at large, has been growing progressively smaller for well over a decade.

Two committee members Sen. Jack Reed, a Rhode Island Democrat, and Sen. Joseph I. Lieberman, a Connecticut independent, said they back the Navy's request for authorization to start a new round of negotiations with the builders for construction of seven submarines over a five-year period beginning in 2009.

But Reed and Armed Services Committee Chairman Carl Levin they are not yet ready to embrace the accelerated shipbuilding budget under consideration in the House.