The Japanese authorities announced earlier this week they would ready their Self-Defense Forces against a possible threat from the expected launch of a North Korean long-range rocket, which could come as early as Monday.

Tokyo dispatched four MIM-104 Patriot surface-to-air (SAM) missiles to Japan’s southern border, while another three were placed near the capital. The systems are aimed at blasting away possible rocket debris, or otherwise warding off any other threat to Japanese territory.

Pyongyang angered the international community after its December 1 announcement that it would attempt another rocket launch, the country’s second this year.

While North Korean authorities have claimed the rocket will attempt to send a satellite into outer space, the international community has condemned what it believes to be the development of an intercontinental ballistic missile (ICBM) program meant to ferry nuclear warheads.

South Korean media reports, quoting unnamed sources in Seoul, have indicated that North Korean technicians have already mounted the rocket on its launch pad. The launch window will remain open until December 22.

A previous attempted launch of a North Korean rocket last April ended in failure after the rocket exploded shortly after lift-off.