Japan has decided to develop for the first time long-range, air-to-ship cruise missiles that can be carried by fighter jets and are capable of attacking a warship from beyond the range of enemy weapons, government sources said Sunday.

The plan is aimed at boosting deterrence by extending the range of available missiles to more than 400 kilometers, as China has been improving its naval capabilities, the sources said.

Planned development work will be based on Japan’s existing supersonic XASM-3 air-to-ship missiles, which are said to have a range of not more than 200 km, they said.

The Defense Ministry plans to include costs for the new project in its draft budget.

At the Diet in January, Prime Minister Shinzo Abe said he believes long-range cruise missiles are not banned under the Constitution.

Article 9 of the supreme law renounces war as a sovereign right of the state, banning the possession of military forces and other “war potential.”