South Korean acting President Hwang Kyo-ahn (centre, front) inspected a variety of firearms during a firing drill north of Seoul on Wednesday.
The US is to tighten sanctions on North Korea and step up diplomatic moves aimed at pressuring the country to end its nuclear and missile programmes.
President Donald Trump’s strategy was announced after a special briefing for all 100 US senators.
Earlier, the top US commander in the Pacific defended the deployment of an advanced missile defence system in South Korea.
Tensions have risen amid fears the North is planning new weapons tests.
“The United States seeks stability and the peaceful denuclearisation of the Korean peninsula,” said a joint statement issued by Secretary of State Rex Tillerson, Defense Secretary Jim Mattis and Director of National Intelligence Dan Coats.
“We remain open to negotiations towards that goal. However, we remain prepared to defend ourselves and our allies.
“The president’s approach aims to pressure North Korea into dismantling its nuclear, ballistic missile, and proliferation programs by tightening economic sanctions and pursuing diplomatic measures with our allies and regional partners,” the statement added.
The Americans are deeply concerned about advances in North Korea’s weapons technology, they believe it could well be capable of hitting the United States with a nuclear warhead before the end of President Trump’s first term.
Any US military intervention to pre-empt that would be fraught with risk, but Mr Trump has toughened his rhetoric to drive home a message that it’s a credible threat.
A key part of his plan is to pressure China to lean more heavily on North Korea to dismantle its nuclear weapons programme. The statement says the US is open to negotiations towards that end, but many even in Washington doubt the regime could ever accept such terms.