Russia has blocked a Western-led effort at the UN Security Council to both condemn the chemical attack in Syria, and push Moscow's ally President Bashar al-Assad to cooperate with international inquiries into the incident.
The latest veto on Thursday (local time) saw Russia block a draft resolution backed by the United States, France and Britain to denounce the attack, and require Assad's government to provide access for investigators and information, such as flight plans.
This is the eighth time during Syria's six year civil war that Moscow has used its veto power on the Security Council to shield Assad's government.
China, which has vetoed six resolutions on Syria since the civil war began, abstained from the vote, along with Ethiopia and Kazakhstan.
Ten countries voted in favour of the text, while Bolivia joined Russia in voting no.
The toxic gas attack on April 4 prompted the US to launch missile strikes on a Syrian air base and widened a rift between US and Russian relations.
Russian President Vladimir Putin said on Thursday that trust had eroded between the two countries under US President Donald Trump.
US Secretary of State Rex Tillerson reiterated that comment after meetings with Russian leaders in Moscow, and said that relations are at a low point with a low level of trust.
Mr Tillerson also called for Assad to eventually relinquish power.
Mr Trump has voiced caution on his relationship with Mr Putin, and said he would wait and see about future ties with Moscow.
Trump said the US is "not getting along with Russia at all" and relations between the two global powers are at an "all-time low".
However, Trump also said Mr Tillerson's Moscow meetings went better than expected.
US Ambassador to the United Nations, Nikki Haley, called on Moscow to stop protecting Assad, and said the US wants to work with Russia toward a political solution for Syria.
Ms Haley told the 15-member Security Council that Russia, "Once again, has chosen to side with Assad, even as the rest of the world, including the Arab world, overwhelmingly comes together to condemn this murderous regime".
"If the regime is innocent, as Russia claims, the information requested in this resolution would have vindicated them".
Russia's deputy UN envoy, Vladimir Safronkov, said the draft resolution laid blame prior to an independent investigation.
Mr Safronkov said he was "amazed" that this was the conclusion.
"No one has yet visited the site of the crime. How do you know that?"
Syria's government has denied responsibility for the gas attack that killed at least 87 people, many of whom were children.
A fact-finding mission from the Organisation for the Prohibition of Chemical Weapons (OPCW) is investigating the attack.
If it determines that chemical weapons were used, then a joint UN/OPCW investigation will look at the incident to determine who is to blame.