North Korea held its rhetoric against the United States on Monday, while South Korea said Pyongyang might be making plans for its sixth Nuclear Test. The Seoul Intelligence Service (NIS) told South Korean lawmakers in a closed-door parliamentary assembly that it has revealed signals that North Korea is preparing for another round of nuclear tests at its new Punggye test site.

Speculation of when North Korea plans to carryout another round of nuclear test has been rift, this year has been abundant, along with some great successes in the North Korea's nuclear history.

The latest Pyongyang’s nuclear test was in September when it detonated what it claimed to be a small nuclear weapon that was small enough to mount on a rocket, although analysts say the claim is difficult to verify.

North Korean missile and nuclear weapons program

Kim Byung-kee, a lawmaker from the Democratic Party (PD) of South Korea, said NIS reported that North Korea has completed its nuclear test preparations in Tunnel 2 and Pungoming- new. He added that NIS said it had detected activities that indicate tunnel 4 was prepared for more construction work after excavation stopped last year.

In a statement to reporters, North Korean officials said the United States faced major penalties for carrying its latest US-South military drills on the peninsula.

The Ulchi Freedom Guardian military exercises, launched on August 21, are held annually and observed by South Korea and the United States as purely defensive in nature.

Joint US-South Korea military drills

But North Korean officials told reporters that this year's drills come to the worst possible time of heightened tensions.

Officials say if there is an escalation, with catastrophic consequences, Americans will be entirely responsible. Meanwhile, Pyongyang has continued to test a number of rocket launchers, including a triple launch on Saturday. The three missiles Pyongyang turned off in this test were short-distance Scud motors, General Jeong Kyeong-Doo, US General Chiefs of Staff said on Monday.

South Korean President's office said on Saturday that officials believed North Korea could have launched 300mm missile rockets from a rocket launcher. A South Korean military official said US and South Korean officials continue Saturday's launch analysis, where two missiles traveled 250 miles above sea level, and another exploded immediately after the start.

It is the first missile test since North Korea successfully launched two intercontinental ballistic missiles in July, which is said to be able to reach the continent in the United States, which drew widespread condemnations from world leaders and attracted expanded UN Security Council sanctions on Pyongyang.