The official added the South Korean and the US militaries are also paying “close attention” to the possibility -- raised by Russian lawmaker Anton Morozov -- that North Korea might conduct another ballistic missile test.

Having finished a five-day visit to Pyongyang on Friday, Morozov told Bloomberg that the North Korean officials had informed him that they were preparing to test a long-range missile, which they hope could reach the west coast of the US.

Tension on the peninsula has risen in recent weeks over the North’s nuclear and missile tests, with Trump threatening to “totally destroy” North Korea if it threatens the US and North Korean leader Kim Jong-un responded by calling Trump deranged and saying he would pay dearly for his threat.

The tit-for-tat appears to show no signs of abating as North Korea leader Kim Jong-un on Saturday reaffirmed the country’s nuclear program as a “powerful deterrence” against the US, while Trump said “only one thing will work” in dealing with North Korea.

Trump’s comment appears to indicate that military action is on his mind, though the president did not make clear to what he was referring. When asked by reporters later about the cryptic tweet, he said, “You’ll figure that out pretty soon.”

Some security officials and analysts noted that North Korea would likely wait for the “perfect timing” to maximize the impact of its provocations and demonstrate defiance against mounting economic sanctions and international condemnation.

“North Koreans always have a good sense of timing,” former CIA analyst Sue Mi Terry, Bower Group Asia’s managing director for Korea, told Voice of America. “(North Korean leader) Kim Jong-un will show that he lives up to his ‘Rocket Man’ billing.”

During his speech at the Central Committee of the Worker’ Party on Saturday, Kim pledged to continue its parallel development of nuclear weapons and the economy and claimed its economy has grown despite the economic sanctions, according to the state media on Sunday. 

Yong Suk Lee, deputy assistant director of the CIA’s Korea Mission Center, said he had instructed his staff to “stand by (their) phones” in the event that the North stages provocations on and around Oct. 10 Korean Workers Party’s founding day, which coincides with the Columbus Day holiday in the US.

President Moon Jae-in’s national security adviser Chung Eui-yong highlighted a similar timeline, saying that the North would act around Oct. 10 -- as well as Oct. 18, when China is slated to hold the 19th National Congress of the Communist Party.

In a bid to implement UN sanctions on North Korea over its nuclear and missile programs, China has ordered all North Korean-owned businesses in the country to close by early January. China has long been considered the main backer of the reclusive regime.

“If North Korea coincides its provocations with China’s party congress, it would be a pressuring card against Beijing. It’s like sending the Chinese a message and asking them to do something.” said Kim Yong-hyun, a professor of North Korean studies at Dongguk University in Seoul.

By Yeo Jun-suk(jasonyeo@heraldcorp.com)