The Hague: Syrian authorities "abetted by Russia's continuing efforts to bury the truth" still possess and use chemical weapons, an American diplomat told the international chemical weapons watchdog on Thrusday.
The strong comments by Kenneth D Ward, the American ambassador to the Organization for the Prohibition of Chemical Weapons, came amid ongoing diplomatic skirmishes over last week's deadly attack in Syria.
Ward used a hastily convened meeting of the organization's executive council to launch a withering verbal attack on Syrian President Bashar Assad and his allies in Moscow.
The meeting was called to discuss the April 4 attack on the Syrian town of Khan Shaykhun that killed nearly 90 people. The United States and other Western governments blame Assad's regime.
Washington in retaliation launched missile strikes on a Syrian air base they say was the starting point for the chemical weapons attack, a move that ratcheted up tensions between the United States and Syria's ally Russia.
Russia and Syria claim the Khan Shaykhun victims were killed by toxic agents released from a rebel chemical arsenal hit by Syrian warplanes.
Assad, in an interview with Agence France-Presse, denied that any chemical weapons attack took place.
"Definitely, 100 percent for us, it's fabrication," Assad said in the video released by his office.
"Our impression is that the West, mainly the United States, is hand-in-glove with the terrorists. They fabricated the whole story in order to have a pretext for the attack," Assad said in his first comments since the US missile strikes in response to the chemical attack.
Assad denied having chemical weapons and said Syria would only allow an "impartial" investigation into the incident. But in a statement Thursday, the OPCW said its Director- General Ahmet Uzumcu told the meeting at the group's headquarters in The Hague that the preliminary assessment by OPCW experts investigating the alleged use of chemical weapons was "that this was a credible allegation."
He said investigators have collected samples that have been sent for analysis.
US ambassador Ward insisted it was a deliberate attack that amounted to "a direct affront to the Chemical Weapons Convention and, indeed, a direct affront to human decency, carried out by a State Party" to the OPCW, according to the text of his speech that was posted on the organization's website.