North Korea has accused the United States of conducting more than 180 aerial sorties in December to spy on the communist country.
The official Korean Central News Agency quoted an unnamed military source as saying that the sorties were carried out by U2 spy planes and other reconnaissance aircraft.
It said the flights were carried out in preparation for a surprise attack by Washington, in a bid to stifle North Korea by strength.
North Korea regularly issues such statements, which the US usually refuses to comment on.
The latest claim comes as efforts continue to restart six-nation talks on North Korea's nuclear weapons programme.
China, the two Koreas, the United States, Japan and Russia held inconclusive talks in August aimed at persuading North Korea to give up its nuclear ambitions.
Correspondents say Beijing has continued to play a key role in seeking to convey North Korea's concerns to the West.
The nuclear crisis was sparked in October 2002 when Washington accused Pyongyang of having a secret nuclear weapons programme in violation of a 1994 agreement.
Pyongyang has since pulled out of the Nuclear Non-Proliferation Treaty and announced it had started reprocessing its spent nuclear fuel rods.