ABC News February 6, 2018

UN investigators say they are probing alleged chlorine gas attacks in Syria

WATCH: US calls alleged chlorine attacks in Syria a 'troubling pattern'

U.N. war crime investigators said Tuesday they are probing multiple reports that bombs containing weaponized chlorine have been used against civilians in two rebel-held towns in Syria.

Paulo Pinheiro, head of the U.N. Commission of Inquiry on Syria, said the commission had “alarmingly” received several reports that chlorine gas had been used in attacks on the towns of Saraqeb, in the northwestern Idlib Province, and Douma in Eastern Ghouta near Damascus.

Omar Haj Kadour/AFP/Getty Images
Syrians reportedly suffering from breathing difficulties following Syrian regime air strikes on the northwestern town of Saraqeb, rest at a field hospital in a village on the outskirts of Saraqeb, due to the lack of hospitals in the town, Feb. 4, 2018. Five people were treated for "suffocation" after Syrian regime air strikes on the northwestern town of Saraqeb, the Britain-based Syrian Observatory for Human Rights reported, adding that 10 civilians were killed in southern Idlib province.

Since the beginning of the year, Idlib has seen an increase in fighting, with 250,000 civilians reportedly fleeing the violence, according to Pinheiro.

"These reports are extremely troubling, and make a mockery of the so-called 'de-escalation zones' intended to protect civilians from such bombardment," he said in a statement.

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Martial Trezzini/Keystone via AP, FILE
Brazilian Paulo Sergio Pinheiro, Chairperson of the Commission of Inquiry on Syria, wipes his eyes during a press conference about the launch of the 14th report of the Commission of Inquiry on Syria on its investigations of alleged human rights violations committed by all warring parties between March 1 and July 7, 2017, at the European headquarters of the United Nations in Geneva, Switzerland, Sept. 6, 2017.

Pinheiro said the number of attacks in Idlib and Eastern Ghouta had increased dramatically in the past 48 hours, leading to multiple reports of civilian deaths. Airstrikes reportedly hit at least three hospitals in Ma’aret al Nu’man, Kafr Nabl and Mardikh in Idlib, he said.

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A Syrian girl holds an oxygen mask over the face of an infant at a makeshift hospital following a reported gas attack on the rebel-held besieged town of Douma, in the eastern Ghouta region, on the outskirts of Damascus, Syria, Jan. 22, 2018.

On Sunday, Al-Ma’ara National Hospital in Ma’aret al Nu’man was forced to close after six airstrikes targeted it, according to the Syrian American Medical Society, which supports the hospital. No deaths were reported, but patients, including eight premature babies, had to be transferred to nearby hospitals to continue their treatment, SAMS said in a statement.

Since the beginning of the year, there have been 34 attacks on health care facilities in Syria, according to SAMS.