Experts from the Organization for the Prohibition of Chemical Weapons (OPCW) have been sent to Turkey to collect samples, as part of an investigation into the alleged chemical attack in Syria on April 4, Reuters reported Thursday citing sources.

The investigation mission was launched by OPCW to gather bio-metric samples in Turkey and interview survivors.

The alleged chemical attack killed at least 80 civilians in the rebel-held town of Khan Sheikhoun in northwest Syria. The US launched 59 Tomahawk missiles toward a Syrian airfield on April 7 in response to the attack. The Syrian government has denied that it conducted such an attack, a stance backed by Russia.

Russia's Ministry of Defence responded on April 5 by saying "the Syrian aviation made a strike on a large terrorist ammunition depot and a concentration of military hardware," where rebels were, according to the ministry's statement, producing " chemical warfare munitions."