A South Korean Aegis combat system-equipped destroyer, patrolling in the East Sea, has assumed the key mission of detecting North Korea's launch of a long-range rocket, government sources said.

North Korea hinted at the possibility of firing a rocket, which it claims to be carrying a satellite, in the coming weeks to mark the 70th anniversary of the Workers' Party of Korea on Oct. 10.

The Aegis ship equipped with a state-of-the-art radar system is aimed at countering North Korea's ballistic missile threats, according to one of the sources.

It detected North Korea's long-range rockets in 2009 and 2012 shortly after they were launched.

The Navy is considering deploying one more Aegis destroyer in the East Sea, another source said.

"If North Korea fires off a long-range rocket, it will likely be before or after the founding anniversary of the WPK," the source noted.

 There is no specific sign of any imminent rocket launch yet, however, Defense Ministry spokesman Kim Min-seok said earlier this week.

South Korea and the United States are keeping a close watch on the North's moves, he added. (Yonhap)