TOKYO, Jan. 19 (UPI) -- The possibility North Korea has the capability to miniaturize nuclear warheads cannot be ruled out, according to a Japanese government official.
"North Korea is a very closed society and one cannot say for certain, but based on North Korea behavior and the nuclear test of Jan. 6, this is the government's judgment," said Akira Nagatsuma, a politician of the opposition's Democratic Party of Japan.
Yonhap reported Tokyo has made similar claims in the past, when tensions escalated due to North Korea provocations in 2013.
The Japanese government also stated its national missile defense system was ready to respond to multiple ballistic missiles headed for Japan.
In South Korea, Defense Minister Han Min-koo again condemned the North's fourth nuclear test, saying that it was a provocation that threatens the peace and stability of the Korean peninsula and the world, South Korean outlet News 1 reported.
"It is true North Korea is determined and ready to conduct nuclear tests," Han said Tuesday. "The test has been a source of great concern for South Koreans."
The magnitude of the seismic activity during the test, however, has been considered to be too weak for a hydrogen bomb test, according to officials in Washington and Seoul.
In Pyongyang, praise from state media outlets for the test continued to flow.
North Korea's Rodong Sinmun stated Tuesday that the world's eyes were all turned to Korea, and slammed North Korea collapsists in the United States and elsewhere.
"Comrade Kim Jong Un has declared a nuclear attack is a possibility against those who threaten or violate our sovereignty," Pyongyang said in statement.