"The firing of the ballistic missile of this time is extremely problematic in terms of safety of aircraft and ships", Yoshihide Suga, Japan's chief cabinet secretary, told reporters in an emergency news conference.
"Japan absolutely can not tolerate North Korea's repeated provocative actions".
"We continue to monitor North Korea´s actions closely", PACOM said in a statement.
"The United States government is aware", the White House official said.
Chinese State Councilor Yang Jiechi is scheduled to arrive in Tokyo on Monday for talks with Shotaro Yachi, the head of the National Security Council, Japan's foreign ministry said in a statement.More news: Ariana Grande Honors Bombing Victims, Will Return to Manchester for Benefit Concert
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Already, he added, North Korea posed a "direct threat" to the USA and its neighbors.
World leaders are grappling with how to halt provocations by the isolated nation, with South Korea's President Moon Jae-in seeking engagement while U.S. President Donald Trump and Japanese Prime Minister Shinzo Abe take a harder line. He stressed that the fact that Pyongyang possesses "hundreds of artillery cannons and rocket launchers" within range of South Korean capital of Seoul would make the potential conflict particularly unsafe.
The North's Scud missiles using liquid fuel is known to have a range of 300-500 km, mainly targeting the South.
After the test, Kim said the weapon system's ability to detect and track targets had "remarkably" improved and its accuracy also increased, according to the official Korean Central News Agency.
There was no immediate comment from the North's state controlled media.
North Korea has also boasted about its plans to develop a missile capable of striking the United States and has ignored all calls to halt its weapons programs, insisting that it's necessary to counter US aggression.
Over the past few months, the young leader has overseen several military drills, including the test-firing of a medium-range ballistic missile last Sunday, as Washington seeks to ramp up pressure on Pyongyang to curb its nuclear ambitions.
The new reported launches come amid heightened tension in the Korean peninsula after global condemnation of several banned ballistic missile tests this year.