Russia vetoed a US draft resolution at the UN Security Council Tuesday that would have established an independent investigation into the suspected use of chemical weapons in Syria.
The US draft condemned the suspected attack by the Assad regime in Douma, demanded immediate access for humanitarian workers to the region and called for an inquiry.
"When the people of Douma, along with the rest of the international community, looked to this council to act, one country stood in the way. History will record that," US Ambassador to the UN Nikki Haley said. "History will record that on this day, Russia chose protecting a monster over the lives of the Syrian people."
"Russia has trashed the credibility of the council," she added.
Swedish Ambassador Olof Skoog called Russia's veto a "tragic d-j- vu."
In November, Russia blocked the renewal of the independent panel investigating chemical weapons in Syria, and British Ambassador Karen Pierce reminded the council that Tuesday's vote marked Russia's sixth veto related to chemical weapons in Syria.
Seven nations -- including the US -- voted against a Russian resolution that would have set up an investigation overseen by the Security Council.
According to Haley, that draft was designed to give Russia a chance to approve the investigators who were chosen for the task and allow the Security Council to assess the findings of the investigation before any report was released.
A second Russian resolution that only supported the Organization for the Prohibition of Chemical Weapons fact-finding mission in Syria also failed to pass.
While Haley and Russian Ambassador Vassily Nebenzia were seen greeting each other with handshakes and kisses on the cheek prior to the meeting, the mood quickly changed as the diplomats hurled accusations at each other.
Prior to vetoing the US draft, Nebenzia said that by putting the resolution forward for a vote "the delegation of the United States is once again trying to mislead the international community and making yet one more step toward confrontation."
On Monday, Haley told the Security Council that the US will respond to the Assad regime's alleged chemical attack against Syrian civilians as she excoriated Russia, saying its hands are "covered in the blood of Syrian children."
"Chemical weapons have once again been used on Syrian men, women and children," Haley said at Monday's meeting to discuss what appeared to be a chemical attack on Douma, the last rebel-held town in Syria, on Saturday that left 49 people dead and scores injured.
"History will record this as the moment when the Security Council either discharged its duty or demonstrated its utter and complete failure to protect the people of Syria," Haley said. "Either way, the United States will respond."
Images of gasping children struggling to breathe shocked the world and galvanized President Donald Trump, who condemned the attack as "sick" and attacked Russian President Vladimir Putin and Iran for supporting Syrian President Bashar al-Assad.