South Sudan to join Chemical Weapons Convention

South Sudan is joining the Chemical Weapons Convention outlawing the use of toxic arms, a global watchdog said on Friday, leaving just three nations left to sign on to the treaty.

Juba has almost concluded the process to become the body's "newest and youngest state party” top foreign ministry official Moses Akol Ajawin said, according to a statement from the Organisation for the Prohibition of Chemical Weapons (OPCW).

"South Sudan has no reason to sit on the fence," Ajawin told the annual meeting of the OPCW.

The move leaves Israel, Egypt and North Korea as the only countries yet to join the arms treaty which came into force in 1997.

"The images of victims of chemical weapons make us all the more appreciative of the goals and objectives of OPCW," Akol Ajawin said.

"As such, we, in South Sudan, would unreservedly like to associate ourselves with the noble goals and objectives of this great organisation."

The move was welcomed by OPCW chief Ahmet Uzumcu, who said: "Today, we are one step closer to universal membership."

"I urge the other nations that have yet to join the convention - Egypt, Israel and North Korea - to unite with the rest of the world in eliminating all chemical weapons forever."

A total of 192 nations have already signed up to the convention, and more than 96 percent of the planet's declared chemical weapon stockpiles have been destroyed under OPCW verification.

South Sudan is the world's newest nation, having gained independence from Sudan in 2011.

But it has been embroiled in a civil war since December 2013 that erupted when President Salva Kiir accused Riek Machar, his former deputy, of plotting a coup.

On Tuesday, the United States threatened to take unspecified measures against South Sudan's government unless it moves to end the conflict and stop harassing UN peacekeepers and aid workers. 

Last year, the US unsuccessfully pushed for an arms embargo on South Sudan and international sanctions on senior officials.