North Korea's foreign minister Ri Su Yong (pictured above) told the UN in Geneva that Pyongyang had the power to carry out a "pre-emptive strike" on the US.
Ri made the comment ahead of the UN Disarmament Conference held in the Swiss city on Tuesday.
He said joint US-South Korea military exercises, which started on Monday, were "unprecedentedly provocative in nature" and could spark a war.
"The DPRK (Democratic People's Republic of Korea) cannot but bolster its nuclear deterrent capability to cope with the ever-increasing nuclear threat of the US," Ri told the Geneva delegation. "Now the DPRK has the power of deterring the US and conducting a pre-emptive strike as well if necessary."
His rare speech sparked a swift rebuke from the US ambassador Robert Wood who urged Pyongyang to stop making threats and "rid itself of nuclear weapons."
"We call on the DPRK to immediately cease all threats, reduce tensions and take the necessary steps towards denuclearisation needed to resume credible negotiations," Wood said, referring to six-party talks that collapsed in 2008.
The US envoy also said the exercises with South Korea, which have been held for almost 40 years, were "transparent and defence-oriented" and in full compliance with the armistice ending the 1950-1953 Korean War.
The annual joint exercises had triggered military tensions in recent years between the Koreas.
Rhetorical threat amid further missile testing
North Korea fired two short-range Scud missiles into the sea off its east coast on Monday, according to South Korean officials.
South Korea's Yonhap state news agency also reported on Tuesday that Pyongyang could be preparing to test fire a medium-range missile.
Ri, speaking ahead of the Geneva forum, said the divided Korean Peninsula was a "touch-and-go nuclear powder-keg".
Missile tests have been carried out by the North in recent years in reaction to what it considers provocative behaviour by Seoul and its western allies.
Despite Seoul and Washington insisting that their joint military exercises are purely defence-based in nature, they are regularly condemned by Pyongyang as "provocative rehearsals for the invasion."
lw/jil (AFP, Reuters)