In Washington, a U.S. official told CNN North Korea could test fire mobile ballistic missiles any time. That assessment by the Obama administration is based on latest intelligence showing the Communist country has likely completed its launch preparation, CNN reported.
The official said such a North Korean test could occur even without the country sending out the standard warning notice to commercial aviation and maritime shipping, CNN reported. The official, however, noted the information is based only on satellite imagery without any information on the ground.
In South Korea, military officials told Yonhap News Seoul and Washington upgraded their surveillance status Wednesday to monitor any North Korean missile test as that country was believed to have completed preparations for a mid-range launch from its east coast, where two Musudan missiles, brought by rail last week, had been mounted on mobile launchers.
A senior South Korean military official told Yonhap the Combined Forces Command has raised "Watchcon" 3 status, a normal defense condition, by one level to step up surveillance monitoring and increase the number of intelligence staff.
The Musudan missile, which has never been tested before, can travel up to 2,500 miles when fired from a transporter-erector-launcher, the report said. Such a range could threaten the U.S. Pacific base in Guam.
Seoul officials say next Monday could be one of the dates for a North Korean missile launch as April 15 marks the birthday of the late Kim Il Sung, grandfather of current North Korean leader Kim Jong Un. They say North Korea can also fire off several missiles from different sites.
"There are clear signs that the North could simultaneously fire off Musudan, Scud and Nodong missiles," a government source told Yonhap.
In Japan, Prime Minister Shinzo Abe told reporters Wednesday his government is making all preparations to defend against any North Korean missile.
"We are taking every possible measure to protect Japanese people's lives and safety," Abe said, Kyodo News reported.
The report said a North Korean missile firing could come as early as Wednesday. The preparations include setting up warning systems to provide information to local governments and the public.
On Tuesday, Japan's Defense Ministry deployed Patriot Advance Capability-3 missile interceptor units in the Tokyo area. It has also deployed Aegis destroyers, which are equipped with SM-3 interceptor missiles, in the Sea of Japan to monitor North Korean activities.
Notable deaths of 2014 [PHOTOS]