Updated 5:09 PM ET Annan's deputy, Jean-Marie Guehenno, told reporters after the U.N. Security Counci briefing that diplomats are deeply troubled by Syria's cycle of violence. "I believe that in the council there's an understanding that any sliding toward full-scale civil war in Syria would be catastrophic, and the Security Council now needs to have that kind of strategic discussion on how that needs to be avoided," Guehenno said in Geneva after speaking to the New York-based Security Council by videoconference. Guehenno also warned of the possibility of outside groups and terrorists taking advantage of the violence. "In any situation where there is a risk of civil war you have opportunistic actors, if one can say that, that can try to exploit that," he said. Guehenno said he told the closed session of the 15-nation council that Annan's six-point peace plan to end the 15-month conflict must be fully implemented and that political process must include talks between the Syrian government and the opposition. "It's very important that the Security Council be united in pushing for a political process," Guehenno said. Dmitry Peskov, President Vladimir Putin's spokesman, was quoted as saying by the ITAR-Tass news agency Wednesday that "there can be no talk" about a shift in Russia's stance on Syria under foreign pressure. Russia, along with China, has twice shielded Syrian President Bashar Assad's regime from the U.N. sanctions over his crackdown on protests. Syria is Russia's last ally in the region, providing Moscow with its only naval base outside the former Soviet Union and a top customer for Russian weapons industries. David Cohen, Treasury undersecretary for terrorism and financial intelligence, said the toll taken by sanctions on Syria are "mounting day by day." "They're drawing down their reserves without a ready means of replenishing those reserves," Cohen said. The White House also blamed Iran for stirring up violence inside Syria and said Assad's fall would be a huge blow to Tehran. The United States is increasingly linking Syria and Iran rhetorically and tactically, applying economic pressure with and without help from the United Nations or other countries. Iran is Syria's only staunch defender in the Middle East, and the Syria crisis has united Sunni Arab neighbors who see in Syria a way to weaken Iran, their main Shiite enemy. "I won't speak for any other government," White House press secretary Jay Carney said in Washington. I would simply say that it is our belief, and it's the belief that we express in these conversations, that supporting the Assad regime is placing oneself or one's nation on the wrong side of history.