WASHINGTON — The Obama administration said Monday that U.S. military and civilian personnel have completed the destruction of the Syrian government’s declared chemical weapons stockpile, heralding the neutralization of the agents aboard a U.S. ship as a watershed moment in the Syrian conflict.

The completion of the effort, President Barack Obama said in a statement, “advances our collective goal to ensure that the Assad regime cannot use its chemical arsenal against the Syrian people and sends a clear message that the use of these abhorrent weapons has consequences and will not be tolerated by the international community.”

The effort was conducted under the auspices the Organization for the Prohibition of Chemical Weapons and the United Nations. Last month, a Danish container ship transferred the Syrian government’s stockpile of chemical agents to the MV Cape Ray, a 648-foot-long U.S. vessel, in the Italian port of Gioia Tauro.

The Cape Ray made for international waters in the Mediterranean Sea, where it used custom-made equipment to diffuse the chemical agents – 620 tons of substances used as precursors for sarin and other chemical weapons – into polluted water.

“In record time, even amid a civil war, we removed and have now destroyed the most dangerous chemicals in the regime’s declared stockpiles,” Secretary of State John Kerry said in a statement. “But much more work must be done.”

Kerry said there are still “discrepancies and omissions related to Syria’s chemical weapons declaration.”

He also highlighted the continued use of chlorine gas against Syrian civilians by the government of President Bashar Assad, while reaffirming U.S. support of moderate rebels.

“The United States will continue to provide political, financial, and other support to the moderate opposition,” Kerry said, “because we are committed to help those who seek the right of all Syrians to choose a future of peace and oppose the violent extremists who exploit the chaos and ruin that Assad has brought to Syria.”

On Monday morning, Secretary of Defense Chuck Hagel called Navy Capt. Rich Dromerhauser, to congratulate him and the Cape Ray crew for eliminating the stockpile.

“While the international community’s work to completely eliminate Syria’s chemical weapons program is not yet finished, the secretary believes this is a clear demonstration of what can be achieved when diplomacy is backed by a willingness to use military force,” said Rear Adm. John Kirby, the Pentagon press secretary.