U.S. Ambassador to the United Nations Nikki Haley delivers remarks at a security council meeting at U.N. headquarters during the United Nations General Assembly in New York City, U.S. September 21, 2017. REUTERS/Stephanie Keith

NEW YORK (Reuters) - U.S. Ambassador to the United Nations Nikki Haley on Thursday described Russian interference in U.S. elections as “warfare.”

U.S. intelligence agencies have concluded that Russia used cyber-enabled means in an attempt to help President Donald Trump win the White House, an allegation the Kremlin has denied.

“We have to be so hard on this and we have to hold them accountable,” Haley said during a panel discussion with former Secretaries of State Madeleine Albright and Condoleezza Rice held by the George W. Bush Institute in New York on Thursday.

“When a country can come interfere in another country’s elections that is warfare. It really is, because you’re making sure that the democracy shifts from what the people want,” she said. “This is their new weapon of choice and we have to get in front of it.”

Congressional committees and special counsel Robert Mueller are investigating alleged Russian interference in the election, including whether there was any collusion between Trump associates and Moscow. Trump has denied that there was any collusion between his campaign and associates and Russia.