North Korea has warned that the US mainland is within range of its missiles and said Washington's recent agreement to let Seoul possess missiles capable of hitting all of the North shows the allies are plotting to invade the country.
Seoul announced on Sunday that it had reached a deal with Washington which would allow it to nearly triple the range of its missiles to better cope with North Korean missile and nuclear threats.
Now North Korea has called the deal a "product of another conspiracy of the master and the stooge" to "ignite a war" against the North.
In a statement carried by the official Korean Central News Agency, a spokesman at the powerful National Defence Commission said the North would bolster its military preparedness.
"We do not hide... the strategic rocket forces are keeping within the scope of strike not only the bases of the puppet forces and the US imperialist aggression forces' bases in the inviolable land of Korea but also Japan, Guam and the US mainland," he said.
South Korea's defence ministry said it had no official comment on the North's statement, but Seoul and Washington have repeatedly said they have no intention of attacking North Korea.
North Korean long-range rockets are believed to have a range of up to about 4,160 miles, putting parts of Alaska within reach, according to South Korea's defence ministry. But the North's patchy record in test launches raises doubts about whether it is truly capable of an attack.
Pyongyang shocked Japan in 1998 when it sent a rocket over Japan's main island and into the Pacific. That also alarmed Washington because about 50,000 US troops are deployed in Japan and their bases could be within the North's range. Tokyo and Washington have since intensified their ballistic missile defences.
But the North's most recent rocket launch, in April, ended in humiliating failure shortly after lift-off.
North Korea said it was trying to launch a satellite with that launch, but the US and other countries said it was actually a test of long-range missile technology. The failure suggests that Pyongyang has yet to master the technology it needs to control multi-stage rockets - a key capability if it is to threaten the United States with intercontinental ballistic missiles.