The United States will do everything in its power to extend the international arms embargo on Iran under discussion at the United Nations, Secretary of State Mike Pompeo said on Friday.

The U.N. Security Council has started voting on a U.S. bid to extend the embargo on Iran, which is opposed by veto-powers Russia and China, with results due on Friday.

Pompeo, on a visit to Austria, said Iran must also provide full and immediate cooperation with the International Atomic Energy Agency nuclear watchdog, whose head he was meeting in Vienna.

Some diplomats say the attempt to extend the ban is bound to fail and put an already fragile nuclear deal between Tehran and world powers further at risk.

"It makes no sense to permit the world's largest state sponsor of terrorism to purchase and sell weapons systems," Pompeo told a news conference. "I mean, that's just nuts."

Pompeo said he was urging the rest of the world to support the U.S. stance.

"We are going to do everything that we can within our diplomatic tool set to ensure that arms embargo doesn't expire," he said.

"The voting will be in the next handful of hours and we are hoping that we will be successful. When we see the results we will make the decision about how to move forward.

"We have been unambiguous about the fact we no intention of allowing this arms embargo to expire. None whatsoever."

Pompeo welcomed the agreement between Israel and the United Arab Emirates to normalise diplomatic ties.

"It's an important step forward for Middle East stability," Pompeo said. "It's a good moment for the world and its security."