S. Korea joins PSI after North`s nuke test

South Korea, angered by North Korea`s second nuclear test, announced Tuesday that it will fully participate in a U.S.-led nonproliferation campaign.

Seoul made the decision to join the Proliferation Security Initiative (PSI) following the North`s April 5 rocket launch, but it had delayed a formal announcement in consideration of its efforts to resume dialogue with the communist neighbor, Yonhap News said.

Government officials said there was no reason to wait any longer as North Korea carried out another nuclear experiment on Monday.

"The government has decided to endorse the PSI Statement of Interdiction Principles to counter serious threats posed by the spread of weapons of mass destruction and missiles," foreign ministry spokesman Moon Tae-young said in a statement.

But an inter-Korean maritime agreement signed in 2005 will remain valid, he added.

The PSI is aimed at stopping the trafficking of weapons of mass destruction. South Korea will be its 95th member.

The initiative, launched in 2003, does not directly target any country, but North Korea, long suspected of exporting illicit weapons and parts, is understood to be a main target. North Korea has repeatedly warned that the South`s participation in the PSI would be tantamount to a declaration of war.

South Korea`s previous liberal administration rejected the U.S. request for Seoul to take part in the PSI, citing "unique geopolitical situations" on the divided peninsula, the words Seoul uses in referring to its tricky relations with the North. South Korea has only been an observer to the offshore exercises.

But the current conservative administration, one of whose slogans is "Global Korea," said Seoul should play a bigger role in cracking down on the international black market for weapons and related technology.

The government also puts top priority on strengthening its alliance with the U.S. in its foreign policy.

In an outdoor speech in Prague hours after the North`s April 5 rocket launch, U.S. President Barack Obama expressed his will to bolster the PSI.