Russia warned Tuesday of an "uncontrollable escalation" as the United States presses to extend an arms embargo on Iran or impose UN sanctions that could kill a nuclear deal. "We cannot accept an attempt to get a blessing for the US-desired maximum pressure policy through the Security Council, to legitimize it," the Russian ambassador to the United Nations, Vasily Nebenzia, told a Security Council session. "What we get in the end is an uncontrollable escalation," he said. sct/ft