The United Nations Security Council has rejected an appeal from UN aid officials for a monthlong humanitarian cease-fire in Syria amid separate calls by the United States for Syria and its ally Russia to end their attacks against rebel-held areas.

Russia on February 8 opposed the call for the cease-fire requested by Kuwait and Sweden and supported by the United States and France, calling it unrealistic.

"We would like to see a cease-fire, the end of the war, but the terrorists, I am not sure, are in agreement," Russia's UN envoy, Vassily Nebenzia, told reporters.

Russia, along with Iran, has offered military and diplomatic support for Syrian President Bashar al-Assad in its nearly seven-year civil war and has opposed any moves that could potentially weaken his position.

The United States and Turkey back differing rebel groups fighting Assad’s government, which often refers to U.S.-supported rebels as "terrorists" along with fighters from the Islamic State (IS) extremist group.

All sides are fighting against IS extremists, who are attempting to hold on to the group's final enclaves after being driven out of most of the territory it captured in 2014.

On February 6, Panos Moumtzis, the UN humanitarian coordinator for Syria, called for the monthlong cease-fire to reach civilians in need as fighting in the Syrian areas of Eastern Ghouta and Idlib escalated.

In a closed-door Security Council session, UN aid chief Mark Lowcock appealed for the cease-fire to allow humanitarian aid to reach besieged civilians.

But diplomats say the cease-fire request was rejected. An agreement requires approval by a majority of the 15 members and no veto by the five permanent members -- the United States, Russia, United Kingdom, France, and China.

'Middle-Ages-Style Siege'

Before the meeting, French Ambassador Francois Delattre appealed for an immediate cease-fire and unimpeded access for aid workers.

"Eastern Ghouta is experiencing a Middle Ages-style siege. That is totally unacceptable," Delattre told reporters.

"In Syria, we are now back to the darkest period of this conflict, with the highest death toll among civilians over the last year," he said.

Separately, the United States demanded that Assad's forces and Russia end their air strikes and alleged chemical attacks against areas held by U.S.-backed rebels of the Syrian Democratic Forces (SDF).

Damascus has repeatedly denied using chemical weapons.

The U.S.-led coalition on February 7 said its air and local ground forces in Syria killed more than 100 pro-Syrian fighters in "self-defense" after an "unprovoked attack" on the SDF's headquarters.

The Pentagon said coalition advisers had been with SDF forces when the base was attacked 8 kilometers east of the Euphrates River deconfliction line in Deir al-Zor Province.

State Department spokeswoman Heather Nauert said on February 8 that the United States was "extremely concerned about escalating violence" in Idlib Province, the Eastern Ghouta area near Damascus, and other areas "threatened by ongoing regime and Russian air strikes."

“We are yet again appalled by the recent reports of the Assad regime's use of chemical weapons and the escalation of bombings that has resulted in dozens of civilian deaths in the last 48 hours,” the statement said.

According to UN statistics, some 13.1 million Syrians are in need of humanitarian aid, including 6.1 million who have been displaced within the country during the civil war, which began in 2011 with a government crackdown against pro-democracy protesters.

With reporting by AFP, AP, and Reuters

