Western powers rejected a Russian bid at the United Nations to halt Turkey's military actions in Syria, as France warned of a dangerous escalation in the nearly five-year conflict.
The emergency Security Council meeting came as US Secretary of State John Kerry cautioned there was "a lot more work to do" for a ceasefire to take hold in Syria, following talks in Geneva between American and Russian officials.
Meanwhile President Barack Obama, in a phone call with Turkey's President Recep Tayyip Erdogan, urged the Ankara government and Kurdish YPG forces to "show reciprocal restraint" in northern Syria.
The elusive truce was meant to begin Friday, but failed to materialize as fighting raged in Syria with Kurdish-led forces backed by US-led air power seizing a key town from the Islamic State group.
Russia, which has been carrying out air strikes in support of Syrian leader Bashar al-Assad's forces, has urged the UN to press Turkey to halt its shelling of Kurdish forces in the country's north.
Smoke billows following reported air strikes by Syrian government forces in a rebel-held area of Daraa in southern Syria, on February 17, 2016.
Moscow presented a draft resolution that "strongly demands" an immediate end to cross-border shellings and plans -- supported by Turkey -- for foreign ground intervention in Syria.
But the text failed to garner support from key council members with at least six countries including veto-wielding France and the United States rejecting it outright during a closed-door meeting, diplomats said.
US Ambassador Samantha Power accused Moscow of trying to "distract the world" from its air campaign in support of the Syrian regime and urged it to abide by UN resolutions supporting a peace process.
"Russia must understand that its unconditional support to Bashar al-Assad is a dead-end and a dead-end that could be extremely dangerous," French Ambassador Francois Delattre said.
"We are facing a dangerous military escalation that could easily get out of control and lead us to uncharted territory," he said.
Turkey is pressing for a joint ground operation in Syria with its international allies, insisting it is the only way to stop the war.
Turkish Ambassador Yasar Halit Cevik said his country was facing "national security threats emanating from Syria" in reference to the Kurdish militias it is targeting in the country's north.
Fighters from the Syrian Democratic Forces guard a post on the outskirts of the northeastern town of Al-Hol, in the Syrian Hasakeh province on November 7, 2015.
Amid the surge in fighting, UN peace envoy Staffan de Mistura said a new round of peace talks scheduled for February 25 was unlikely.
Kurds seize town from IS
In his call with Erdogan, Obama stressed that Kurdish YPG forces "should not seek to exploit circumstances in this area to seize additional territory, and urged Turkey to show reciprocal restraint by ceasing artillery strikes in the area," a White House statement said.
Obama, in an apparent reference to Russia, also "urgently called for a halt to actions that heighten tensions with Turkey and with moderate opposition forces in northern Syria, and undermine our collective efforts in northern Syria to degrade and defeat ISIL."
French President Francois Hollande said Ankara's escalating involvement in the conflict was creating a risk of war between Turkey and Russia.
"Turkey is involved in Syria... There, there is a risk of war," Hollande told France Inter radio.
On the ground, the Kurdish-led Syrian Democratic Forces (SDF) alliance -- which groups the powerful Kurdish People's Protection Units (YPG) and smaller Arab groups -- seized the northeastern town of Al-Shadadi from IS, with backing from US-led air strikes, a monitor and Kurdish sources said.
Al-Shadadi was the largest town controlled by IS in Hasake province, and the defeat extends earlier losses for the jihadists there.
Members of the civil defence pull a boy out from under the rubble following air strikes by suspected Russian planes on the Syrian city of Aleppo.
SDF forces earlier seized a nearby oilfield from IS and cut the routes from Al-Shadadi to Mosul in neighboring Iraq as well as IS's de facto Syrian capital Raqa.
The SDF began a new operation in Hasakeh on Tuesday, following major advances by its forces in northern Aleppo province, where it has seized territory from Syrian rebel groups.
Its advances in Aleppo have angered Turkey, which says the YPG is the Syrian affiliate of the Kurdistan Workers' Party (PKK), an outlawed group that has waged a decades-long insurgency against Ankara.
Turkey has carried out nearly a week of shelling against SDF positions in Aleppo, intensifying its fire Friday and expanding it to target the Kurdish town of Afrin, where two civilians were killed, the Observatory said.
A group of coalition forces, which includes YPG, gather on a hill top in al-Hol in the Syrian Hasakeh province on November 2, 2015.
Ankara fears the SDF advance in Aleppo province is intended to connect Kurdish-held areas in northern and northeastern Syria, creating an autonomous Kurdish region along much of its southern border.
TAK claims Ankara bombing
On Friday, Erdogan repeated accusations that the YPG was behind a Wednesday bombing in Ankara that killed 28 people. The YPG denied the charges.
However the little-known Kurdistan Freedom Falcons (TAK), a group linked to the PKK, claimed responsibility, saying it was revenge for military operations in southeast Turkey. The group warned foreign tourists not to visit the country.
The PKK says the TAK is a splinter group over which it has no control.
The TAK rose to prominence after it claimed that it fired mortar shells on Istanbul's Sabiha Gokcen airport on December 23.
Saudi Foreign Minister Adel Jubeir meanwhile raised the prospect that Syrian rebels could be supplied with surface-to-air missiles, though he said it was not a decision Riyadh would take alone.
Syria's conflict is now approaching its sixth year, with more than 260,000 people killed and half the population displaced.