In a dramatic show of defiance, South Korean protesters put up quite a show on Tuesday.

Setting off fireworks attached to the bottom of dummy rockets, the 150 protesters condemned North Korea's planned satellite launch in April.

Pyongyang says it's using the rocket to launch a satellite, to mark the 100th anniversary of the birth of the country's founding ruler Kim Il-sung.

(SOUNDBITE) (Korean) CONSERVATIVE ACTIVIST CHOO SEON-HEE SAYING:

"North Korea is threatening our sovereignty as they develop nuclear weapons and missiles. We're here to condemn the North and to protect our right to live."

South Korea's foreign ministry said North Korea's plan was a disguised attempt to develop a long-range ballistic missile capable of delivering nuclear weapons.

(SOUNDBITE) (Korean) SOUTH KOREA'S FOREIGN MINISTRY SPOKESMAN CHO BYUNG-JAE SAYING:

"We're consulting closely with the international community and concentrating our diplomatic efforts to stop North Korea's provocations. At the moment, all options are open in terms of UN-level measures."

The United Nations nuclear watchdog said it had received an invitation from North Korea to visit, three years after its inspectors were expelled from the reclusive state.

The North has twice tested a nuclear device, but experts doubt it has the ability to place an atomic bomb, atop a warhead.

Sophia Soo, Reuters.