Syrian state-run media said Tuesday that the Syrian army was responding to a shelling attack in Damascus by "armed groups" - an attack that they say killed five people, including two children, and injured 13 others.
A Twitter account affiliated with Turkey's so-called Operation Olive Branch in Syria claimed Tuesday that forces affiliated with the Democratic Union Party-a leading Syrian Kurdish political party that commands the armed and US -backed People's Protection Units (YPG)-fired a mortar shell containing toxic chlorine gas at Turkey-backed Free Syrian Army (FSA) insurgents in northern Afrin, injuring up to 20.
Meanwhile, the lead investigator of a United Nations -mandated Commission of Inquiry on Syria said his team was looking into reports that bombs allegedly containing weaponized chlorine were used on two recent occasions, in the town of Saraqeb, in Idlib, and Douma, in Eastern Ghouta.
Turkish President Tayyip Erdogan ramped up his verbal assault on the U.S. role in Syria on Tuesday, saying USA forces should leave Manbij, a Syrian city held by YPG-allied forces with support from a US-led anti-Islamic State coalition.
At least 80 people were killed on Tuesday in government air and artillery strikes on besieged areas of the capital Damascus.
"The United States is gravely alarmed by continued allegations of the use of chlorine gas by the Syrian Regime to terrorize innocent civilians, this time in Idlib Province near Saraqib", State Department spokeswoman Heather Nauert said in a statement Monday.
Foreign Minister Jean-Yves Le Drian told BFM TV on Wednesday that "all indications show us today that the Syrian regime is using chlorine gas at the moment". The offensive against Idlib hit hospitals over the weekend while a suspected chlorine gas attack on the town of Saraqeb caused 11 people to struggle to breathe, according to medics.
Syria war: United Nations calls for truce as government pounds rebel enclave
Reports of air strikes hitting at least three hospitals in the past 48 hours "make a mockery of so-called 'de-escalation zones", he said.
The White Helmets said airstrikes targeting the village of Termala in Idlib on Tuesday killed three people.
On Tuesday, President Rouhani also said the US military presence in Syria is meant to "disintegrate" the war-stricken country.
The commission past year reported that the Syrian government forces had used highly toxic sarin nerve gas on a rebel-held area in the country.
USA ambassador to the UN Nikki Haley clashed with her Russian counterpart at a meeting of the Security Council on Monday after proposing a statement condemning Damascus "in the strongest terms". The president of Syria Bashar-al-Assad in conjunction with the Russian Airforce and militias backed by Iran are pursuing military operations against the rebels in the last significant redoubts of the regions that have been in control of Assad's opponents in the western side of the country.
"When Tillerson comes we will share these ideas with him sincerely, we will share our expectations", he said.
The Russian pilot who was shot down over Syria on Saturday blew himself up with a grenade to avoid being captured by rebels, according to Russian media.