South Korea's intelligence agency believes North Korea may develop an Intercontinental ballistic missile (ICBM) that can reach the US mainland this year as Pyongyang is likely to conduct more missile tests soon.

The agency has spotted brisk movement of vehicles near known missile facilities, and authorities believe North Korea may have conducted missile engine tests. Yi Wan-young, a member of South Korea's parliamentary intelligence committee, revealed the same after being briefed by the National Intelligence Service (NIS).

Yi mentioned that there were no signs of any nuclear tests yet in the region. However, he also noted one of the tunnels at the Punggye-ri complex, where nuclear tests are likely to happen, is ready for another detonation at any time now, Reuters reported.

There is another tunnel under construction, says the report.

"The agency is closely following the developments because there is a possibility that North Korea could fire an array of ballistic missiles this year under the name of a satellite launch and peaceful development of space, but in fact to ratchet up its threats against the United States," the South Korean lawmakers told the media after a briefing by the spy agency.

Despite the UN Security Council sanctions, North Korea continues to develop its nuclear weapons and missile programme. They have been quite open about their plans to develop missiles that can possibly reach the US. The rogue state has maintained that their pursuit of weapons and arms technology is to defend against American invasion on their lands. however, the US denies any such intentions.

North Korea is also conducting a thorough ideological scrutiny of the political unit of their military for the first time in 20 years, said Kim Byung-kee, another member of the committee.

In October, it was reported that North Korea was building a new submarine to launch its ballistic missiles. While they are unlikely to build one that can outsmart an American sub, it could mean that a nuclear weapon can be transported closer to targets. Considering the pace at which North Korea is developing their missiles, it is anyone's guess if the country's leader, Kim Jong-un, would actually fire at his rivals if he gets the chance.