(ANSA-AFP) - THE HAGUE, NOV 28 - Russia's invasion of Ukraine has increased the threat from weapons of mass destruction including chemical munitions, the head of the world's toxic arms watchdog said on Monday. The Organisation for the Prohibition of Chemical Weapons (OPCW) was closely monitoring the situation in Ukraine, its chief Fernando Arias told the regulator's annual meeting. "The situation in Ukraine has again increased the real threat posed by weapons of mass destruction, including chemical weapons," Arias told the meeting in The Hague. "It has exacerbated existing tensions to a point where unity of the international community on common global challenges related to international security and peace cannot be presumed." International disarmament bodies like the Nobel Peace Prize-winning OPCW "now have become places for confrontation and disagreement", Arias lamented. Threats and allegations about the possible use of nuclear, chemical and biological weapons have been traded since the war in Ukraine began in February, but with no evidence they have been deployed. (ANSA-AFP).