UNITED NATIONS — U.S. Ambassador Nikki Haley warned Wednesday that the U.N.’s failure to hold Syria accountable for its use of chemical weapons because of Russia’s opposition has made the world “a far more dangerous place.”

She told the Security Council that its lack of action on Syria has led others to take notice, pointing to the use of nerve agents against North Korean leader Kim Jong Un’s half-brother in Malaysia and the poisoning of a former spy and his daughter in England.

“This reveals a dangerous trend,” she said, urging a renewed commitment by the Security Council to end the use of chemical weapons in Syria and elsewhere in the world.

The council met on the first anniversary of a chemical attack using sarin nerve gas on the Syrian rebel-held town of Khan Sheikhoun that killed about 100 people.

In a joint statement marking Wednesday’s anniversary, the U.S., Britain, France and Germany criticized Russia for vetoing the extension of the expert body from the U.N. and the Organization for the Prohibition of Chemical Weapons that blamed the Syrian government for four chemical weapons attacks including Khan Sheikhoun.

The four countries condemned the use of chemical weapons anywhere and vowed to ensure that those responsible are held accountable.

Haley brought Syrian Dr. Mamoun Morad to the council meeting, saying he was one of the only doctors on duty in Khan Sheikhoun on April 4, 2017.

She quoted his words on the attack: “It was like Judgment Day, the Apocalypse. You just can’t even describe the scene, can’t even begin to scratch the surface of explaining what happened. We didn’t have any protective equipment for gas.”

Haley called the doctor, who treated victims of many other attacks in Khan Sheikhoun as well, “a hero.”

She accused President Bashar Assad’s regime of still using chemical weapons “practically every other week,” including “credible reports of chlorine gas attacks” in the Damascus suburbs of eastern Ghouta which the government seized recently.

Russia’s U.N. Ambassador Vassily Nebenzia urged the council to accept Moscow’s proposal for a replacement for the U.N.-OPCW expert body to assess responsibility for Syria chemical attacks. But the U.S., Britain, France and others oppose it because it would require Security Council approval of the experts’ determination, effectively giving Russia veto power over its decisions.

Nebenzia said Russia condemns any use of chemical weapons, “however real ones, not imagined ones.”

“At the same time as some are running after phantoms of chemical weapons in Damascus, in the region dangerous chemical weapons terrorism potential continues to be masked,” he warned without elaborating.

Nebenzia then called for an open Security Council meeting Thursday afternoon on the poisoning of the ex-spy and his daughter in the English town of Salisbury. He said Russia was guided in seeking the meeting by the principle it shares that any chemical weapons use “is not acceptable and must be investigated and perpetrators punished, and that impunity is unacceptable.”

Britain’s U.N. Ambassador Karen Pierce had earlier told the council “there should be no more victims of chemical weapons attacks, whether they take place in the war zone of Syria or in an English country town.”

She accused Russia of calling a meeting of the OPCW on the Salisbury attack in The Hague, Netherlands, on Wednesday “to pre-empt the findings of the OPCW investigation” of the nerve agent used on ex-spy Sergei Skripal and his daughter. She noted that a Foreign Ministry official in Moscow has already rejected the idea that Russia would accept the OPCW’s conclusions.

Pierce also criticized Syria for failing to answer 21 serious issues about “gaps, inconsistencies, and discrepancies” in its chemical weapons declaration to the OPCW.

Thomas Markham, the U.N.’s deputy disarmament chief, told the council that discussions between the OPCW and the Syrian government haven’t resolved any of these issues.

“Resolving these outstanding issues will permit shared confidence in Syria’s declaration, within the international community,” he said.