Frustrated by Iran talks, Congress presses for harsher sanctions The proposals, some of which could carry financial risks for U.S. allies as well, have attracted scores of Republican and Democratic sponsors, who say they will push for passage before the August recess. Supporters say the measures would build on sanctions approved last year that helped trim Iran's oil exports by 40 percent. "What we've done so far has been good, but it's clearly not enough," said Rep. Howard L. Berman (Calif.), the ranking Democrat on the House Foreign Affairs Committee, which is drafting a new sanctions bill. The pressure needs to intensify. The search for additional leverage against Iran comes as the Obama administration announced measures intended to expand the list of Iranian companies and individuals covered by existing U.S. sanctions. Treasury Department officials on Thursday named Iran's main oil tanker conglomerate, the National Iranian Tanker Co., to the U.S. blacklist, along with several suspected front companies and financial institutions accused of helping Iran circumvent restrictions on its oil exports. Some of the firms are alleged to have masked the exports by repainting or reflagging oil tankers to conceal the country of origin, Treasury officials said. The administration also tried to strike at Iran's ongoing efforts to acquire nuclear and missile technology, listing 11 individuals and groups said to have aided those efforts. "Iran today is under intense, multilateral sanctions pressure, and we will continue to ratchet up the pressure," David S. Cohen, undersecretary for terrorism and financial intelligence at the Treasury Department, said in announcing the measures. The demand for new sanctions has been building in Congress since last month, when a third round of nuclear talks between Iran and six world powers in Moscow ended with no visible progress toward a deal on reining in Tehran's nuclear activities. White House officials had hoped that Iran would agree to concessions to head off an oil embargo and banking-sector sanctions, both of which took effect two weeks ago. Instead, Iran has rejected demands that it shut down the most controversial parts of its nuclear program, including production of a kind of enriched uranium that can be quickly converted into weapons-grade fuel for nuclear bombs. It has refused requests from U.N. inspectors for access to military facilities that U.S. officials suspect were used to test nuclear detonators. The stalled talks have spurred criticism of the Obama administration's approach to the Iran crisis, leading Republicans and some Democrats to call for more assertive policies, including explicit threats of military force. Supporters of harsher measures point to the White House's resistance to a package of sanctions that was approved by the Senate last year, in a 100 to 0 vote.