The Obama Administration is suspicious Syrian President Bashar Assad might still be hiding chemical weapons and worries those arms could be captured by militants from the Islamic State in Iraq and Syria.

U.S. Ambassador to the United Nations Samantha Power Samantha Jane PowerSupport swells for renaming Edmund Pettus Bridge in Selma to honor John Lewis after his death 'Obamagate' backfires: Documents show Biden, Obama acted properly 'Unmaskings' may be common — and that's the problem MORE said Thursday that there were "discrepancies and omissions" in Syria's declared chemical weapons arsenal.

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"We must ensure that the Syrian government destroys its remaining facilities for producing chemical weapons within the mandated time frames and without the repeated delays by the Assad regime that plagued earlier removal efforts," Power said, according to USA Today.

Power also expressed concern the secret chemical weapons program could be captured by ISIS militants, who have been battling Assad's military in the country's south.

"Certainly, if there are chemical weapons left in Syria, there will be a risk that those weapons fall into [ISIS's] hands," Power added.

Damascus pledged to hand over its chemical arsenal as part of a deal to avert U.S. airstrikes. President Obama had threatened the bombing campaign after evidence surfaced that Syria used chemical weapons against rebels and civilians in the country's brutal civil war.

In June, the White House publicly celebrated the removal of the last declared shipment of chemical weapons from Syria, calling it an "important milestone."

"The removal of these materials sends a clear message that the use of these abhorrent weapons has consequences and will not be tolerated by the international community," White House press secretary Josh Earnest said.

The weapons were subsequently destroyed aboard a U.S. cargo vessel in international waters.

The White House at the time hailed Syria’s compliance with the agreement.

"The fact that Syria has now, you know, declared that they have chemical weapons, signed the treaty and has cooperated with the international community to dispose of those declared chemical weapons is an important step," Earnest said.

"And there was some justified skepticism by people in this room and by other close observers of the situation about whether or not Syria would actually follow through,” he added. “And they did, thanks primarily, again, to the work of the international community to hold them to account to follow through on this mission."