Ankara argues the US-backed Kurdish forces are a "terrorist organization" and has been incensed by Washington's support for the YPG.
On Wednesday, the USA conducted an airstrike against pro-government Syrian militiamen in the economically crucial Middle Euphrates Valley, the informal border between government-controlled and SDF-controlled territory. The IS militants have been dispersed in the province, which also has a number of US bases.
"Kremlin spokesman Dmitry Peskov called the attacks 'precision strikes, ' according to Russia's TASS news agency, and said they were "provoked by the tragic event when terrorists shot down our plane".
By crossing the river, the pro-government forces would have violated the existing de-confliction agreement between Washington and Moscow, approaching USA -backed forces based near an oil field.
President Bashar al-Assad's forces have gained ground in the southern edges of Idlib in recent weeks.
Nebenzya also denied the information that Russian Federation had "blocked" the statement on the humanitarian situation in Syria. "Just as the coalition does not direct the operations of the SDF, the Russians do not direct operations of the Syrian regime".
Sweden and Kuwait requested the meeting of the top United Nations body on Wednesday as Syrian government forces continued to shell rebel-held Eastern Ghouta, killing scores in some of the worst bloodshed in years. The state Al-Ikhbariyah TV said there were reports that dozens were killed.
The official state news agency SANA said the local fighters were battling IS militants and the USA -backed SDF in the area.
SANA called it an "aggression". It later reported that 10 strikes by the coalition had caused "massive destruction". "Everyone is back to their bases", said Abu Khawla, the head of the Deir el-Zour Military Council.
On Wednesday, France's foreign minister said "all indications show us today that the Syrian regime is using chlorine gas at the moment".
Diplomacy is making no progress toward ending a war now approaching its eighth year, having killed hundreds of thousands of people and forced half the pre-war Syrian population of 23 million from their homes, with millions forced out as refugees.
Mitch McConnell says Senate leaders have reached a major budget deal
She declared the agreement "does not have my support, nor does it have the support of a large number of members of our caucus". It would also extend the debt ceiling for another year, reducing fears of an unprecedented US debt default.
The SSRC is promoted by the Syrian government as a civilian research institute but the U.S. accuses the agency of focusing on the development of non-conventional weapons and the means to deliver them.
The U.S. airstrike coincides with escalating violence in Syria.
The campaign by the Syrian government and its ally, Russia, has also battered the northwestern province of Idlib, the largest area under opposition control in Syria.
"Ghouta is drowning in blood", said a doctor in Arbeen, one of the towns in the region in which 100 people were wounded and at least 14 killed, including a rescue worker and several children.
- Double-tap strike - Jisreen was also hit heavily, with 17 civilians killed on Thursday.
But in Eastern Ghouta, 78 people would be counted among the dead before the night was over on Tuesday, another 36 perished on Wednesday and at least 38 on Thursday, according to activists.
Youth in Eastern Ghouta "are being starved, bombed and trapped", said Sonia Khush, Save the Children's Syria response director.
Nauert mentioned the frequency of the use of chemical weapons that have been used on Syrian civilians, which includes an attack last Sunday.
Russian Federation 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. The United Nations decried the "extreme" suffering of civilians in a statement this week, urging a month-long ceasefire nationwide that would allow the urgent transfer of humanitarian aid.
A few days later, Russia started their own peace summit in Sochi - one attended by Russia, Turkey and Syrian government officials, but few from the opposition. It was not immediately clear when the Istanbul meeting would take place.
In a statement, Paulo Pinheiro said the spiraling violence had made "a mockery of the so-called "de-escalation zones" - an agreement reached past year among Russia, Iran and Turkey to stabilize the lines of conflict and open corridors for humanitarian aid. Turkey says its forces are deployed in an observer role.