Russian President Vladimir Putin reiterated his suspicion that the United States or its proxies staged the recent chemicals weapons attack in Syria, saying he believes that neither ISIS nor the Syrian government was responsible.

"I do not remember saying that it was an ISIS provocation," Putin said in an interview with MIR television.

"There are several versions, two of which I consider as priorities. The first is that the Syrian bombs hit a secret chemical weapons facility," he continued. "According to the second version, it was a staged provocation, a deliberate incident designed to create a pretext for increasing pressure on the legitimate Syrian authorities. That is all. But it must be investigated."

That statement increases the clarity of Putin's allegations, as he excludes ISIS as a suspect. Other Russian officials have provided additional detail, particularly by suggesting that the sarin gas was smuggled into Syria from Libya.

"These actions are aimed at creating a new pretext for accusing the government of Syria of more chemical weapons attacks and provoking more strikes by the US," Colonel General Sergey Rudskoy, the head of Operations for the Russian General Staff, said in the Kremlin-run RT.

Western leaders have dismissed such charges and faulted Russia for failing to implement the 2013 agreement to deprive Syrian President Bashar Assad of his chemical weapons stockpiles.

"There's no false flag with respect to calling this what it was, which is a gross offense against international norms and standards," acting State Department spokesman Mark Toner told reporters. "It was crystal clear to us that this was carried out and it was carried out by the Syrian regime."