Dozens of residents of Douma suffocated after a chemical attack hit the suburb of Damascus, leaving 70 dead and others injured.

This attack, which occurred on Apr. 8, was on one of the remaining rebel-controlled territories. It was yet another deadly addition to the country’s seven year civil war, this time causing 500 injuries and 42 deaths directly from the gas. Those affected reported trouble in breathing, foaming from the mouth and nose and burning eyes. Rescuers worked to save citizens from the deadly attack, but found many dead in their homes.

President Trump looked to Russian and Syrian authorities for answers on this crime, but both have denied involvement and the use of any chemical weapons.

“President Putin, Russia and Iran are responsible for backing Animal Assas. Big price to pay… Another humanitarian disaster for no reason whatsoever. SICK!” said Trump on Twitter.

So far, no one has stepped up to take responsibility for the attack, though U.S. officials have confirmed the use of illegal chemical weapons, finding traces of chlorine gas and other nerve agents in medical samples from the victims. The UN is currently working to find solutions, but with differing opinions on how to investigate, they have yet to find anyone responsible.

This news came just days after Trump announced his plans to remove troops from Syria, placing tension on relations between the countries. In response, Trump has promised to take action against Syria. The President warned of possible missile strikes against Syria, though it is still unclear if the US will have an official military response.