Pyongyang agreed to suspend testing long-range missiles in 1999 after the United States eased economic sanctions.
A foreign ministry statement accused the new US adminstration of taking a hard-line stance in its relations with the North.
Pyongyang agreed to suspend testing long-range missiles in 1999 after the United States eased economic sanctions.
Last month, North Korea criticised remarks made by the new US Secretary of State, Colin Powell, in which he referred to the country's leader, Kim Jong-il, as a dictator.
Missile programme
Mr Powell said that George Bush's administration would review Korea policy but was open to engagement with Pyongyang within strict guidelines.
On Thursday, a North Korean Foreign Ministry spokesman was quoted by the official Korean Central News Agency as saying that the country would not remain a "passive onlooker to the things that only hamper scientific and technological development".
Pyongyang agreed with the US in 1999 not to launch long-range missiles as long as it was in talks with Washington.
It proposed that it would abandon its missile programme in exchange for help with the launching of commercial satellites.
Rocket capability
The scheme also included promises of US help for North Korea's devastated economy.
The US has frequently raised concern at the sale of North Korean missile technology to several countries, including Pakistan and Iran.
It is also concerned Pyongyang could build a rocket capable of delivering a bomb over a US city by 2005.
North Korea rattled the world when it test fired a missile over Japan in 1998. Pyongyang insisted the launch was aimed at putting a satellite into orbit.
But it was also seen as a demonstration of the North's ability to fire long-range warheads.