The United States is in talks with Japan to address its concerns over the U.S.-made Aegis Ashore missile defense system, Missile Defense Agency Director Vice Adm. Jon Hill said Thursday, after Tokyo suspended plans to deploy the defense technology earlier this week.

The United States is "working very closely" with Japan to "resolve concerns and issues," Hill said during a virtual defense conference.

David Helvey, acting assistant defense secretary for Indo-Pacific security affairs, was quoted as telling Reuters that the current focus is "having the technical discussion with our Japanese allies to understand the nature of the concerns and to determine the right path forward for this type of cooperation."

The Japanese government decided in 2017 to deploy two land-based Aegis Ashore batteries to beef up the country's defenses against the rapidly advancing North Korean nuclear and missile program.

They were to supplement the Maritime Self-Defense Force's Aegis destroyers, but Japanese Defense Minister Taro Kono said Monday that the government will "halt the process," citing technical and cost issues as well as safety concerns.

Kono has explained that the Defense Ministry found through talks with the United States that hardware modifications, which will likely be costly and time consuming, would be required to ensure the safety of nearby residents during missile interception operations.

Since Japan has no plan to look for alternative sites that would not pose risks to residents, the announced suspension is believed to be the equivalent of scrapping the plan altogether.

According to Kono, Japan and the United States have signed a contract worth around 180 billion yen ($1.7 billion) for the anti-missile system, of which 12 billion yen has already been paid by Japan. Future payments and penalty charges are likely to become an issue hereafter.

Aegis Ashore, a land-based version of the Aegis combat system developed for warships, is a collection of radars, computers and missiles. Japan was supposed to be the third country to introduce the system after Romania and Poland.