united nations -- North Korea, Egypt, Israel, Lebanon and Syria have refused to join a treaty banning chemical weapons, thereby posing a danger to 180 nations that have pledged to destroy stockpiles, the head of a monitoring group said.

Argentine Rogelio Pfirter, director-general of the group that implements the treaty, told the UN General Assembly that all countries should be obliged to join the Chemical Weapons Convention, which came into force in April 1997.

"It is very unfair to other countries if a few countries retain for themselves the privilege of producing chemical weapons when all the others are transparent in this field," said Pfirter, head of the Hague-based Organisation for the Prohibition of Chemical Weapons.

Even one country refusing to join was a "major loophole" in getting rid of such arms, which include the deadly nerve gas VX and mustard gases, he said.

As for North Korea, Pfirter said, Pyongyang has not replied to entreaties to join the convention, despite "allegations of the potential existence of stockpiles." A Security Council resolution on October 14 on North Korea’Äôs nuclear test demanded the nation rid itself of all weapons of mass destruction.

In the Middle East, Egypt, Israel, Lebanon and Syria "in one way or another" contended they could not sign the treaty because of a regional conflict, an excuse Pfirter rejected because so many other countries in war zones have signed.

Of those nations that have declared chemical weapons stockpiles, Russia has the most with more than 40,000 tonnes, followed by the United States with 27,000 tonnes. Other declared holders are India, Libya and Albania.