Hook also said Iran was at the forefront of sponsoring terrorism WASHINGTON: The US is working to renew the arms embargo on Iran, the special envoy to Iran Brian Hook said on Tuesday, adding that sanctions on the Iranian regime had produced "excellent results." Speaking to Brett D. Schaefer of the Heritage Foundation during an online session, Hook said: "The sanctions on Tehran have led to excellent results and we have deprived the Iranian regime of billions of dollars thanks to the sanctions." Hook also said Iran was at the forefront of sponsoring terrorism and added that lifting the arms embargo on Tehran would provide the Islamic Republic "an opportunity to destabilize the region." He said: "Iran is an isolated country and does not enjoy international support," also saying that the US dispute with other countries over policy on Iran was "tactical and not substantive." He continued: "Russia and China want to sell arms to Iran, and the embargo does not suit them." Hook, citing Iran"s attempts to target Saudi Arabia through proxies, said that "not arming Iran contributes to bringing stability to the Middle East," and that preventing the armament of the regime would stop it attacking its neighbors through its proxies. He said US President Donald Trump had been "very strong against Iran," adding that "the Iranian regime is languishing under great pressure and the door is open to diplomacy ... President Trump will continue to pressure and Iran must respond."