A treaty verification body called on Friday on 12 nations including Syria, Iraq and Israel to join a landmark pact for destroying stockpiles of chemical weapons.
The Hague-based Organization for the Prohibition of Chemical Weapons made the appeal ahead of a review conference next week.
So far 183 countries have ratified the 1997 Chemical Weapons Convention banning the use, development, production, stockpiling and transfer of chemical weapons but more states need to join.
"The convention is only as strong as its weakest link and securing universal adherence remains our most important and difficult challenge," Rogelio Pfirter, the watchdog agency's director-general, said in a statement.
Syria, Iraq, Israel, Egypt and Lebanon are among 12 countries that have yet to ratify the convention, the body said.
It pointed to the tens of thousands of deaths and maimings caused by chemical weapons deployed by Iraq against Iranian forces and Iraqi Kurds during the 1980s.
Several of these countries, including at least one from the Middle East, may sign up in the near future, Pfirter said.