It added that the communist nation possesses nuclear weapons to cope with Washington's threats, describing it as a "treasured sword for justice."

"If the US has indeed the guts to confront us in 'rough' manner, we will not necessarily take the trouble to stop it," it said.

The US will be held responsible for "all catastrophic consequences" from a situation when Korea is pushed to the brink of war due to its reckless behavior, said the ministry.

The Trump administration on Friday announced what it calls the strongest-ever sanctions against the North, targeting its vessels, shipping companies and other entities believed to be conducting trade prohibited under previous sanctions.

The move is aimed at preventing the secretive North from exploiting some loophole in existing U.N. sanctions, especially for under-the-radar fossil fuel transactions that allegedly help Pyongyang fund its nuclear weapons and missiles programs. 

 Trump publicly called the measures "the heaviest sanctions ever imposed on a country before.”

“We must continue to stand together to prevent the brutal dictatorship from threatening the world with nuclear devastation,"

he said at a news conference.

If the steps don't work, Trump warned, the US will move to a "phase two" that could be "very, very unfortunate for the world."

The North said the US is trying to completely block its maritime trade amid reports that additional "maritime crackdown" on the North is among the options.

The new round of stand-offs between Pyongyang and Washington came as the two Koreas are in a rare mood of reconciliation, which the North's ministry attributed to leader Kim Jong-un's efforts to improve bilateral ties, bring peace to Korea and ensure the success of the PyeongChang Winter Olympics in the South.

 The North sent athletes to the games along with high-level delegates, including leader Kim Jong-un's influential sister, Kim Yo-jong, to related ceremonies here.

President Moon Jae-in received an invitation to visit Pyongyang for what would be the third inter-Korean summit talks.

Many view the North's recent peace offensive as part of efforts to drive a wedge between the allies and break its longstanding isolation. (Yonhap)