The United States, along with allies South Korea and Japan, will conduct missile tracking exercises starting Monday as tensions with North Korea remains high.

North Korea has showcased its rapidly improving missile and nuclear weapons programs through a series of provocative tests this year. In their last test on Nov. 29, North Korea test-fired an intercontinental ballistic missile (ICBM) that had a range of hitting anywhere in the United States. The November missile marks the third time North Korea has test-launched an ICBM this year.

This is the sixth time that the three countries have shared ballistic missile tracking information, according to Japan’s Maritime Self-Defense Force. Tracking missiles involves a number of ground-based radars and satellites. 

North Korean flew two medium-range ballistic missiles over the Japanese island of Hokkaido earlier this year and has threatened to bracket the U.S. territory of Guam with missiles tests on all sides of the island. Guam is home to two critical U.S. military bases: U.S. Naval Base Guam and Andersen Air Force Base.

Japan is planning on installing a new missile defense system in response to the threat from North Korea. Japanese Defense Minister Itsunori Onodera is asking for funds to build an Aegis Ashore ballistic missile interceptor system. The system is developed by U.S. defense contractor Lockheed Martin. The missile system will also be designed to combat Chinese weapons.

South Korea completed the installation of a Terminal High Altitude Area Defense (THAAD) system in order to counter North Korean missiles in September. 

Given their proximity to North Korea, Japan's proposed system and South Korea's THAAD are not equipped to deal with ICBMs.

The U.S. employs a variety of missile defense systems to defend against missile attacks. The U.S. uses Aegis Systems, THAAD, and a Ground-based Midcourse Defense (GMD). The GMD is specifically designed to counter ICBMS with interceptor missiles launched from California and Alaska.