WASHINGTON -- Lacking assurances from Russia and China that they would approve UN sanctions, the U.S. administration is trying to deny Iran technology, assets and especially weapons to slow down a suspected nuclear weapons program. As part of that campaign, a top U.S. State Department official on Friday urged Russia to drop its plan to sell Tor anti-aircraft missiles to Iran. "We hope and we trust that the deal will not go forward because this is not the time for business as usual with the Iranian government," said Undersecretary of State Nicholas Burns, who has been trying to line up...