The meeting was called by Russian Federation to address US threatened military action in response to last weekend's attack in the Damascus suburb of Douma.
"The immediate priority is to avert the danger of war", said Ambassador Vassily Nebenzia.
"I urge all member states to show restraint in these unsafe circumstances and to avoid any acts that could escalate the situation and worsen the suffering of the Syrian people", Guterres said in a statement.
On Wednesday, he again warned Russian Federation of being an ally of the Assad regime.
And she claimed that Russian Federation simply wanted to stop terrorism in Syria "because we're much closer to Syria than the US".
The statements were significant because the head of the Russian General Staff, Gen. Valery Gerasimov, had previously said the Russian military would respond to US airstrikes that put Russian lives at risk by shooting down the missiles and potentially the ships or planes that fired them.
The Security Council is scheduled to meet on Thursday at the request of Bolivia, which wants to discuss the escalation of rhetoric over Syria and threats of unilateral military action.
The White House said such targeted sanctions would help to ensure that Russian oligarchs profiting from the Kremlin's destabilising activities, including its interference of Western democratic elections in 2016 and 2017, would face consequences for their actions.
"We have proof that last week. chemical weapons were used, at least with chlorine, and that they were used by the regime of (President) Bashar Assad", Macron said, without offering details of any evidence.
Amid the talk of military action, the Kremlin, a close ally of Assad, countered that more "serious approaches" were needed to combat the crisis.
Dozens of people in Douma died and hundreds were injured in the attack, according to the World Health Organization (WHO).
The WHO cautioned that it has no formal role in forensic inquiries into the use of chemical weapons. In a warning to the West against further strikes on Syria, the Russian Defense Ministry said it is now considering arming Assad with Russian S-300 long-range surface-to-air missile systems for the first time.
Top military officials, including Defense Secretary James Mattis, warned Trump during an afternoon meeting Thursday that he risks escalating United States involvement in Syria if he goes forward with the type of aggressive bombing campaign he has pushed over the past week, according to U.S. and Western officials briefed on the conversation.
After six weeks of heavy fighting and an estimated 1,700 civilian deaths in the Eastern Ghouta region, the Syrian government is now said to have control of the area, which lies just outside of Damascus.
The Violations Documentation Center (VDC), which records alleged violations of global law in Syria, said bodies were found with foam at the mouth, discoloured skin and burns to the eyes.
" We hope that there will be no point of return - that the U.S. and their allies will refrain from military action against a sovereign state", Nebenzia informed press reporters late Thursday evening hours.
In the wake of last weekend's gruesome attack, some USA officials advocated a larger, and therefore riskier, strike than the limited action Trump ordered in April 2017, also in response to suspected chemical weapons use.
During his meeting with Trump and the Chairman of the Joint Chiefs of Staff Joe Dunford, Mattis pushed for more evidence of the Assad regime's culpability for the attack, to bolster the case for air strikes, The New York Times reported.
They agreed to "keep working closely" on the issue, Mrs May's office said in a statement. It said another attack with "a number of missiles" targeting a scientific research center destroyed a building and caused other material damage but no human losses.
As fears of a Russia confrontation with Western powers mount, French President Emmanuel Macron expressed his "deep concerns" over the situation in Syria in a phone call with Russian President Vladimir Putin. Two days ago, US President Donald Trump warned that missiles "will be coming" in response to that attack. It "could be very soon or not so soon at all", he said.
"Our president has not yet made a decision about possible action in Syria". Participants included Vice President Mike Pence, Defense Secretary Jim Mattis and John Bolton, Trump's new national security adviser.