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A senior Russian lawmaker on Tuesday dismissed the White House's warning about a potential chemical weapons attack in Syria as a "provocation."

Frants Klintsevich, first deputy chairman of the defense and security committee at the upper chamber of the Russian parliament, accused the U.S. of "preparing a new attack on the positions of Syrian forces.”

"Preparations for a new cynical and unprecedented provocation are underway," he told state-owned RIA Novosti.

The Trump administration said late Monday that it had discovered evidence that the regime of Syrian President Bashar Assad could be planning another chemical weapons attack.

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Syria's President Bashar al-Assad visits a Russian air base at Hmeymim, in western Syria in this handout picture posted on SANA on June 27, 2017, Syria. SANA/Handout via REUTERS ATTENTION EDITORS - THIS PICTURE WAS PROVIDED BY A THIRD PARTY. REUTERS IS UNABLE TO INDEPENDENTLY VERIFY THE AUTHENTICITY, CONTENT, LOCATION OR DATE OF THIS IMAGE - RTS18TY7 (REUTERS)

Press Secretary Sean Spicer said in a statement that "The United States has identified potential preparations for another chemical weapons attack by the Assad regime that would likely result in the mass murder of civilians, including innocent children."

The White House did not detail what prompted the warning.  Several State Department officials typically involved in coordinating such announcements told the Associated Press they were caught completely off guard by the warning, which didn't appear to be discussed in advance with other national security agencies.

However, a non-governmental source with close ties to the White House told AP the administration had received intelligence that the Syrians were mixing precursor chemicals for a possible sarin gas attack in either the east of south of the country, where government troops and their proxies have faced recent setbacks.

U.S. Ambassador to the United Nations Nikki Haley later said that "any further attacks done to the people of Syria will be blamed on Asaad, but also on Russia & Iran who support him killing his own people."

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Syria's President Bashar al-Assad visits a Russian air base at Hmeymim, in western Syria in this handout picture posted on SANA on June 27, 2017, Syria. SANA/Handout via REUTERS ATTENTION EDITORS - THIS PICTURE WAS PROVIDED BY A THIRD PARTY. REUTERS IS UNABLE TO INDEPENDENTLY VERIFY THE AUTHENTICITY, CONTENT, LOCATION OR DATE OF THIS IMAGE - RTS18TY5 (REUTERS)

A Syrian minister has dismissed a White House statement alleging that President Bashar Assad's government is preparing a new chemical weapons attack, saying Damascus has not and will not use such arms.

Ali Haidar, the minister for national reconciliation, told The Associated Press on Tuesday that the White House statement foreshadowed a "diplomatic battle" that would be waged against Syria in the halls of the U.N.

Earlier Monday, Trump dined with Secretary of State Rex Tillerson, Defense Secretary Jim Mattis, National Security Adviser H.R. McMaster and other top officials as he hosted Indian Prime Minister Narendra Modi at the White House.

Assad had denied responsibility for the April attack on the town of Khan Sheikhoun in the rebel-held Idlib province that killed dozens of people, including children. Victims show signs of suffocation, convulsions, foaming at the mouth and pupil constriction.

Days later, Trump launched a cruise missile strike on a Syrian government-controlled air base where U.S. officials said the Syrian military had launched the chemical attack.

It was the first direct American assault on the Syrian government and Trump's most dramatic military order since becoming president months before.

Trump said at the time that the Khan Sheikhoun attack crossed "many, many lines," and put the blame squarely on Assad's forces.