North Korea said on Saturday it would consider any interference with its satellite operations a declaration of war and would mobilise its war deterrence if any attack against its strategic assets were imminent.

Pyongyang would respond to any U.S. interference in space by eliminating the viability of U.S. spy satellites, state media KCNA reported, citing a statement from North Korea's defence ministry spokesperson.

"In case the U.S. tries to violate the legitimate territory of a sovereign state by weaponizing the latest technologies illegally and unjustly, the DPRK will consider taking responsive action measures for self-defence to undermine or destroy the viability of the U.S. spy satellites," the statement said.

DPRK are the initials of the North's official name, the Democratic People's Republic of Korea.

North Korea says it successfully launched its first military spy satellite on Nov. 21, transmitting photos of military installations in the U.S. mainland, Japan and the U.S. territory of Guam.

A U.S. Space Command spokesman, asked if Washington had the capability to interrupt the North Korean satellite's reconnaissance operations, said the U.S. was could deny an adversary's space capabilities using a variety of means, according to U.S. broadcaster RFA.

The United States on Thursday targeted North Korea with fresh sanctions after the launch, designating foreign-based agents it accused of facilitating sanctions evasion to gather revenue and technology for its weapons of mass destruction programme.

South Korea on Friday blacklisted 11 North Koreans for involvement in the country's satellite and ballistic missile development, banning them from financial transactions.