North Korea is believed to be preparing to launch another ballistic missile in retaliation for a forthcoming joint naval drill by the US and South Korea.
The US Navy said on Friday that the USS Ronald Reagan aircraft carrier will lead the drill in the coming week, as another show of force against dictator Kim Jong-un's ongoing nuclear and weapons programme.
Pyongyang immediately renewed its threat to fire missiles at the US Pacific territory of Guam, warning that "reckless moves" by the US would compel it to take action.
North Korea first threatened Guam in August after Donald Trump warned the pariah regime would "face fire and fury like the world has never seen". Kim backed down temporarily but said he would watch for US provocation. Tensions have only escalated since. A fresh missile test may also be on the cards.
The Dong-A Ilbo daily, citing a government source, reported yesterday that satellite images showed ballistic missiles mounted on launchers being transported out of hangars near Pyongyang and in the North Pyongan Province.
The source said US military officials believe the movement could indicate preparation for a test launch of a missile comparable to the Hwasong-14 inter-continental ballistic missile (ICBM) or Hwasong-12 intermediate-range ballistic missile (IRBM).
Another probability could be the testing of the new Hwasong-13 ICBM (solid engine) that has a longer maximum range than the Hwasong-14.
Initially it was expected that North Korea would carry out a provocative test last Tuesday, to mark the anniversary of its ruling party's foundation.
However, speculation is now rising that the deployment of the US carrier strike group and nuclear-powered submarine to the Korean Peninsula may provide a fresh trigger for action.
"The North may carry out a simultaneous launch of ICBM and IRBM within a few days, in protest against the US's show of military might," a source told the Dong-A Ilbo.
The USS Ronald Reagan will conduct the 10-day joint drills in waters east and west of South Korea.
Starting tomorrow, the exercise will check the allies "communications interoperability and partnership," the US Navy's 7th fleet said in a statement.
As many as 40 navy vessels, including the Aegis destroyer, and attack helicopters will be deployed.
Meanwhile, the USS Michigan, an 18,000-ton submarine, which arrived in the South Korean port of Busan on Friday, is also expected to join the exercise.
Although Washington and Seoul insist that regular joint drills are defensive in nature, North Korea considers them to be rehearsals for invasion and has lashed out with weapons tests in the past.
The deployment comes at a time of heightened tension between the US and North Korea, with both President Trump and Kim Jong-un trading regular insults.
"The US military action hardens our determination that the US should be tamed with fire and lets us take our hand closer to the trigger for taking the toughest countermeasure," said a North Korean foreign ministry official, reported by state-run news agency KCNA on Friday.
Earlier this week the US flew two supersonic heavy bombers over the Korean peninsula, staging the first night-time joint aviation exercises with Japan and South Korea.