The Navy’s brand new littoral combat ship Milwaukee — in service fewer than three weeks — broke down Friday and required a 40-nautical mile tow back to Joint Expeditionary Base Little Creek, Va.

The cause of the breakdown was “an engineering casualty” preliminarily diagnosed as fine metal debris in the lube oil filter which caused a complete loss of propulsion, the Navy Times reported.

The ship was commissioned last month in Milwaukee, and was en route to San Diego via the Great Lakes when she broke down.

In a statement to the Navy Times, Republican Senator John McCain called the propulsion issues “deeply alarming.”

“Reporting of a complete loss of propulsion on USS Milwaukee (LCS 5) is deeply alarming, particularly given this ship was commissioned just 20 days ago,” McCain said. “U.S. Navy ships are built with redundant systems to enable continued operation in the event of an engineering casualty, which makes this incident very concerning.

“I expect the Navy to conduct a thorough investigation into the root causes of this failure, hold individuals accountable as appropriate, and keep the Senate Armed Services Committee informed.”