After DPRK launch of a missile over its territory, Japan has deployed a Patriot Advanced Capability-3 (PAC-3) missile defense system at a US military base in Tokyo as part of a previously scheduled drill.
Japan's Prime Minister Shinzo Abe on Tuesday said DPRK's launch of a missile over its territory was an "unprecedented, serious and grave threat" as he called for an emergency UN Security Council meeting.
Abe vowed to enhance pressure on the nuclear-armed state as tensions spike over Pyongyang's weapons development ambitions.
"Their outrageous act of firing a missile over our country is an unprecedented, serious and grave threat and greatly damages regional peace and security," he told reporters in Tokyo.
"We have protested to North Korea (the DPRK)."
Calling for an emergency meeting of the UN Security Council, he said Japan would "strongly call for increased pressure on DPRK in cooperation with the international community".
South Korea's Joint Chiefs of Staff said in a statement that Tuesday's missile was launched at around 20:57 GMT Monday from Sunan, near Pyongyang, and travelled east "and over Japan".
Tokyo has been on edge over DPRK launches since a mid-range ballistic missile flew without warning over the northern part of the country and into the western Pacific in 1998.
A decade later, in 2009, a DPRK projectile passed over Japanese territory without incident, triggering Tokyo's immediate denouncement.
At the time DPRK said it was launching a telecommunications satellite, but Washington, Seoul and Tokyo believed Pyongyang was testing an ICBM.