While the Pentagon rethinks and restructures its Littoral Combat Ship (LCS), the U.S. has agreed to help Japan develop its own coastal warship with similar attributes.

Recent Pentagon guidance directs the U.S. Navy to halt negotiations for any more LCS contracts less than halfway through the service’s proposed 52-ship buy, as the Defense Department reviews other options to make the vessels more lethal and survivable.

The headquarters for U.S. Forces in Japan confirms that the two countries will collaborate on a littoral warship. The initiative was first revealed in a statement from the Japanese Ministry of Foreign Affairs.

The statement says Japanese Foreign Minister Fumio Kishida and Ambassador Caroline Kennedy “exchanged a document on March 4 in Tokyo concerning studies for joint development between the government of Japan and the United States for optimization of the high-speed littoral combat ship under the bilateral Mutual Defense Assistance (MDA) agreement,” according to an unofficial translation.

The exact details of what the warship would be are still sketchy. The U.S. State Department, which reportedly worked out the deal, did not reply to queries. The U.S. Navy and Defense Department said they were unaware of any such agreement, and the U.S. Embassy in Japan directed queries to the foreign affairs ministry.

The prime contractor for one of the LCS industry teams in the U.S., Lockheed Martin, said it knew nothing of the agreement. Austal USA, the lead of the other team, did not reply to a request for comment.

Asian press reports, however, indicate the ship could be a trimaran, which could make it similar in scope and design to the Austal LCS variant, which displaces roughly 3,000 tons and is an all-aluminum vessel steered by waterjets.

Both LCS versions are marked by their high speeds. They are being developed to perform countermine, antisubmarine and surface warfare missions, using interchangeable mission module packages to shift from one task to the other.

The shallow draft, quick speed and flexibility of the ships are deemed ideal for the Asia-Pacific region, regional naval analysts say.