Pentagon
The United States military has concluded that Russians knew ahead of time that chemical weapons would be used in the recent attack in northwestern Syria, according to a senior US official.

The official, who spoke on condition of anonymity since he wasn't authorized to speak publicly on intelligence issues, told The Associated Press on Monday that a Russian surveillance drone was flying over a hospital where victims of the April 4 attack were being brought for treatment.

The senior official claimed that after the drone left the place a Russian-manufactured fighter aircraft bombed the hospital in an attempt to cover up the usage of controversial weaponry.

The United States, however, has no proof of Russian involvement in the actual chemical attack that left more than 80 people dead and dozens others injured in the town of Khan Shaykhun in Idlib province, the official acknowledged.

But the official argued the drone was there because Russians knew the chemical weapons attack was in the process and that victims would be rushing in to get treatment.

The official refused to provide more details for intelligence information which is the basis of the Pentagon's conclusion that Russians were involved in the attack.

Meanwhile, another US official said the Pentagon has not reached a conclusion yet that Russians knew in advance about the alleged chemical attack. That official also demanded anonymity because he wasn't allowed to speak about internal administration deliberations.

The foreign-sponsored militants active in the area and top US officials blamed the chemical attack on the Syrian military whereas Damascus rejected the allegation, insisting it "has never used them [chemical weapons], anytime, anywhere, and will not do so in the future."

Moscow also dismissed the assumption that the Syrian government had anything to do with the attack.

Three days after the alleged chemical attack, two US Navy destroyers fired 59 Tomahawk cruise missiles from the Mediterranean Sea at Syria's al-Shayrat airfield, killing several people and reportedly destroying a number of Syrian aircraft.

US President Donald Trump said he had ordered the strike in response to the chemical attack.

The US military claimed the airfield targeted was used to store chemical weapons and Syrian aircraft. This is while Damascus volunteered to destroy its chemical stockpile in 2014 following a poisonous attack outside the capital.