Sens. Chris Murphy, D-Conn., and Richard Blumenthal, both D-Conn., are urging congressional negotiators to keep intact increased funding for submarine production and design.

The House and Senate both have passed versions of an annual defense policy bill that sets funding limits for the Pentagon. Those versions will now have to be merged, with any differences reconciled.

Murphy and Blumenthal want to ensure that submarine research and development money included in the Senate version of the bill, which is $25 million above what President Donald Trump requested for submarine research and development, is included in the final version of the National Defense Authorization Act for the 2018 fiscal year.

They say the funding can be used to expand opportunities between the Navy, Electric Boat and students at the University of Connecticut and University of Rhode Island.

"Robust funding for undersea research and development will allow the Navy to establish a new initiative to build stronger partnerships between Navy research labs, academia, and the shipyards that build our nation's submarine fleets," the senators wrote in a letter sent Tuesday to the heads of the Senate and House armed services committees.

Conference negotiations on the final version of the defense policy bill have just started.