FILE PHOTO: A United Nations (U.N.) chemical weapons expert, wearing a gas mask, holds a plastic bag containing samples from one of the sites of an alleged chemical weapons attack in the Ain Tarma neighbourhood of Damascus, Syria August 29, 2013. REUTERS/Mohamed Abdullah/File Photo

WASHINGTON (Reuters) - The United States is “very disappointed” that Russia on Tuesday cast a veto at the United Nations Security Council against renewing a mandate to continue an investigation into who was responsible for the use of chemical weapons during Syria’s civil war.

“We are disappointed, we are very disappointed that Russia put what it considered to be political considerations over the Syrian people who were so brutally murdered,” State Department spokeswoman Heather Nauert told a regular briefing.