Japan deployed missile-defense systems at three sites around Tokyo early Tuesday in case of a possible missile launch by North Korea, Chief Cabinet Secretary Yoshihide Suga said, according to CNN.

Japan’s Kyodo news agency said the military (officially called the self-defense force) deployed a Patriot Advanced Capability-3 missile interceptor unit in the Ichigaya district of Tokyo. The move follows Defense Minister Itsunori Onodera's order on Sunday to be ready to shoot down North Korean missiles if they reach Japan. The Japanese navy has sent Aegis cruisers with missile interception capabilities to the Sea of Japan.

The air force's PAC3, also planned for deployment at sites in Asaka and Narashino in the Tokyo metropolitan area, are tasked with covering against any missile attacks on Japan that escape interception by Aegis ships.

On Monday, Suga had said the government would not publicize any missile-defense deployment, saying "It would show our strategy to North Korea."

In an intensifying war of words with South Korea and the United States, the North has threatened to strike American military bases in Japan. Some of those bases are in the greater Tokyo area, a densely populated urban zone of 33 million people.

The United States military also has its own Patriot batteries on bases in Okinawa, the Japanese island that hosts most of the 50,000 American military personnel in the country.