Two U.S. Senators have penned a letter to top U.S. Navy officials criticizing the development of the Littoral Combat Ship program.

Senate Armed Services Committee Chairman Sen. John McCain, R-Ariz., and ranking member Sen. Jack Reed, D-R.I., wrote the letter in response to a report by the Office of Development Testing and Evaluation on the U.S. Navy's Littoral Combat Ships, which noted delays in the program's development.

"To date, the Navy has not yet demonstrated effective capability for either the Mine Countermeasures (MCM) or Anti-Submarine Warfare (ASW) mission packages," the report read.

In the letter, addressed to U.S. Navy Secretary Ray Mabus and Chief of Naval Operations Adm. John Richardson, the senators say assessments of the program by the top Navy officials do not reflect reality.

"More than seven years after the first LCS was delivered, the report makes clear the program remains mired in testing delays with an unclear path ahead," the letter read. "Yet, we seldom hear from Navy leaders about these challenges and the path to achieving full operational capability."

The senators went on to detail further issues with the program, including being unaware how to deploy littoral combat ships with carrier strike groups, and the program's failure to reach initial operating capability after over four years of delays.

The letter also notes that other platforms designed for mine countermeasure capabilities, such as Avenger and Osprey-class ships and Sea Dragon helicopters, have either reached or are approaching initial operating capability, or have had their service lives extended.

"With practically no LCS mission package capabilities proven and only six LCS delivered, we urge you to reevaluate the deployment strategy to ensure employing a greater number of these ships does not come at the expense of completing the integration and testing necessary to give LCS combat capability to meet the already delayed schedule," the letter added.