U.S. President Donald Trump gives a thumbs-up as he and Vice President Mike Pence depart the U.S. Capitol after a meeting to discuss tax legislation with House Republicans in Washington, U.S., November 16, 2017. REUTERS/Kevin Lamarque

WASHINGTON (Reuters) - U.S. President Donald Trump on Thursday urged all members of the U.N. Security Council to back the renewal of the international inquiry into chemical weapons attacks in Syria, saying it was needed to prevent President Bashar al-Assad from using the arms.

“Need all on the UN Security Council to vote to renew the Joint Investigative Mechanism for Syria to ensure that Assad Regime does not commit mass murder with chemical weapons ever again,” Trump said in a note on Twitter.

The 15-nation council was due to vote on Thursday on rival U.S. and Russian bids to renew the international inquiry, diplomats said on Wednesday, a move that could trigger Russia’s 10th veto to block action on Syria.