Eyeing what appears to be increasingly hostile behavior from nearby North Korea, Japan may accelerate roughly $1 billion of planned upgrades to ballistic missile defense systems, Reuters reported Monday.

Those considerations, disclosed to Reuters by three government sources, came just days after United States Strategic Command systems detected a failed missile launch Saturday in the northwest North Korean town Kusong. Japan has been considering the $1 billion budget request that will determine whether to add a new missile defense layer from either Lockheed Martin Corp or from Aegis Ashore.

The budget proposal also includes money that would improve the accuracy and range of PAC-3 Patriot missiles.

Should Japan decide to rollout missile defense systems from either of those companies or seek upgrades to their missiles, it could still take years before those things are implemented. Companies involved in the rocket production like Mitsubishi Heavy Industries and Raytheon Co. are both on tight production schedules, the sources said.

“It nonetheless has symbolic value,” said one of the sources, all of whom were granted anonymity because they aren’t authorized to speak to the media.

North Korea has been implementing major upgrades to their military facilities and weapons systems since 2014. Those efforts have included big investments in defense along the country’s shores to repair ships so the country’s military can patrol farther away from shores and for a longer period of time. They have also invested in ballistic missile capabilities and have sought to enhance their military training facilities.

Recent tests have led some in the international community to express concern that North Korea may act aggressively. The North Korean military has been testing ballistic missiles and in September logged its fifth nuclear test. A nuclear test that was rumored to have been planned for the country’s anniversary tribute to North Korea’s former supreme leader Kim Il Sung last week was reportedly not conducted.