South Korean President Park Geun-hye has said that North Korea is readying a new nuclear test despite strict UN sanctions. The announcement follows reports of increased activity at the North's nuclear test site.
Following various intelligence reports, South Korean officials warned on Monday that North Korea is probably preparing another nuclear test.
"Signs that it is preparing a fifth nuclear test have recently been detected," the South's president Geun-hye Park said during a cabinet meeting.
Although she did not give concrete examples of what points to a possible nuclear test, Park ordered the military to be prepared to deal with provocations from Pyongyang.
The US and South Korean authorities detected two to three times more personnel and vehicle activity at the North's Punggye-ri nuclear test site, reported South Korea's Yonhap news agency on Monday.
On Friday, a US monitoring website saw signs from satellite imagery that the North was looking to produce more plutonium for nuclear weapons.
"Given current activities, we believe that there is a possibility that the North may stage an underground nuclear test, and are monitoring the situation accordingly," South Korean defense ministry spokesman Moon Sang Gyun told reporters.
Analysts believe the recent surge in aggression and nuclear activity in the North may also be linked to leader Kim Jong Un's preparations for an upcoming ruling party congress next month where he will further solidify power.
"It is uncertain what kind of unexpected provocations it would stage," Park said at the cabinet meeting.
Defiant missile tests
A think-tank also announced on Monday that the North is probably able to fit a nuclear warhead onto one of its existing missiles. "From the technical perspective, North Korea is seen as being able to mount a nuclear warhead on its short-range Scud and medium-range Rodong missiles," said Choi Jin Wook, president of the Korea Institute for National Unification.
Although some experts say the North's claims to nuclear warhead capabilities are exaggerated, most acknowledge that the country has made significant strides in its ballistic missile technology.
North Korea conducted a successful launch in February, which led to fresh UN sanctions.
Reports of a fifth nuclear test arose last month when Kim Jong Un ordered nuclear warhead and ballistic missiles tests amidst animosity with the United States and the South over their annual military drills. The drills - which will run until next week - are viewed by the North as an invasion rehearsal.
Last Friday, a missile launch meant to celebrate the birthday of Kim Jong Un's late grandfather ended in failure, according to US officials. However, South Korean media reports claimed that the failed missile was a new, more powerful one, which could possibly strike US military bases in Asia.
rs/jil (AP, AFP, dpa)