"The signing of this agreement will pave the way for the procurement of Tomahawk missiles," a Japanese defense official told reporters on January 18 after the deal was signed in Tokyo.

"Through rational implementation of the (defense) budget, we will significantly enhance our defense capabilities," the Japanese official added.

Japan has approved a record $56 billion defense budget for the next fiscal year starting in April.

The new deal, worth up to $2.35 billion, covers two types of Tomahawk missiles with a range of 1,600km. The deal was approved by Washington in November last year.

Faced with China's growing military might and North Korea's nuclear weapons program, the Japanese government plans to double its defense spending to the NATO standard of 2 percent of gross domestic product by 2027.

Tomahawk is a subsonic, medium to long range (460-2,500km), all-weather cruise missile. It is launched from warships and submarines to attack land targets.

The Tomahawk has undergone numerous upgrades and modifications, including an anti-ship version, an air-to-ground version, and a ground-launched variant.