Reports indicate that U.S. officials believe that the chemical weapon that was used on the Syrian town of Khan Sheikhoun was a nerve agent.
The officials said that the symptoms of those affected and the time at which it was deployed suggest that it was a nerve agent.
Attackers deliver nerve agents early in the morning to maximize on its impact. The time is considered best for the dispersal of nerve agents. The air temperature is coldest near the ground and there is also less air movement, this allows agent stick around.
A statement released on Tuesday by the World Health Organization revealed that the symptoms seen in the victims show that they were exposed to organophosphorus chemicals.
The category of chemicals is known to have nerve agents.
The Russian military has been fighting in support of Assad's government since September 2015. The Kremlin denied carrying out any strikes near the Khan Sheikhoun town. Russian defense ministry spokesman Igor Konoshenkov said the deadly leak came from a rebel workshop used to make chemical weapons.
He said that chemical weapons made by rebels at the site had previously been used by militants in Iraq.The Kremlin has been supporting Assad, who has been fighting rebels trying to overthrow him for more than six years.
One of the U.S. officials who was aware of the intelligence reporting agreed that a nerve agent had been used in the attack. The official also said that sarin was used back in August 2013 in an attack that killed as many as 1,700 Syrian civilians in the town of Ghouta.
The agent was delivered by short-range rockets again early in the morning. Another U.S. official also familiar with the intelligence said that either rockets or artillery was used in the town of Khan Sheikhoun. Witnesses on the ground reported aircraft nearby at the time of the explosion.
Reports from the UN observers said that the chemical had come from the Assad regime's stockpile. The Arab League and the European Union said the attack was carried out by the Assad regime. However, the Assad regime and Russia, blamed rebels.
Following the Ghouta attack, a U.S. and Russian-brokered agreement called for Syria to eliminate its chemical weapons stocks which included sarin. The agreement was successful since huge stocks were shipped out of Syria for destruction throughout 2013 and 2014. The U.S. Intelligence community believed that some chemical weapons were left behind.
The Syrian government was blamed by the United Nations for at least three chemical attacks, including a gas attack via aircraft in Qmenas, Syria in 2015. The Kremlin blamed Monday's chemical attack on a leak from a rebel chemical weapons cache that had been hit by a Syrian government airstrike.
The Organization for the Prohibition of Chemical Weapons (OPCW) said that it was conducting its Fact-Finding Mission (FFM). The mission is set to gather and analyze information from all the sources that are available.
The organization has not provided the time frame within which it will have gathered the facts on the incident. Assad's forces have used chlorine in their attacks on terrorist's targets. This was after the 2013 agreement to eliminate the Syrian stockpile. The use of chlorine is a violation of the Chemical Weapons Convention.