Lockheed Martin, the American defense contractor, said Wednesday it has signed an agreement with Turkish missile manufacturer Roketsan to produce and sell Turkey's SOM-J air-launched cruise missile for Lockheed's F-35 Lightning II Joint Strike Fighter (JSF) combat jet.

JSF is intended to replace a wide range of existing fighter, strike, and ground attack aircraft for the United States and a range of NATO countries.

Ballooning costs

The Wall Street Journal calls it one of the most expensive weapons projects ever and it has been dogged by cost overruns and delays. The current price tag to the Pentagon is $399 billion (315 billion euros). A single plane can cost up to $299 million.

Turkey is a NATO member although it refused to function as a platform for US forces during the Iraq war and recent operations against the Islamic Front in neighboring Syria. Ankara finally agreed on Monday to allow Kurdish fighters across the border to embattled Syrian city Kobani, under siege from IS forces.