Computer Sciences Corp. said on Friday it is negotiating a $1.9 billion extension to a $3.2 billion computer services contract it has with DuPont Co.

The existing 10-year contract is set to expire in May 2007. The new contract would extend the agreement by seven years and seven months. The two companies have an interim agreement in place and plan to complete the contract extension in the fourth quarter, El Segundo-based Computer Sciences said in a press release.

Under the contract, Computer Sciences will continue to run DuPont’s computer networks in more than 40 countries and manage desktop computers in Latin America.

Computer Sciences said separately on Friday that it received a task order from the Navy that could be worth more than $70 million. The company will provide program management and total ship systems engineering support for the US Navy’s DD(X) Destroyer Class Program Office. It has a one-year base period and four one-year extension options.