Sen. Hillary Clinton called for United Nations sanctions against Iran as it resumes its nuclear program and faulted the Bush administration for "downplaying" the threat.

In an address Wednesday evening at Princeton University, Clinton, D-N.Y., said it was a mistake for the U.S. to have Britain, France and Germany head up nuclear talks with Iran over the past 2 1/2 years. Last week, Iran resumed nuclear research in a move Tehran claims is for energy, not weapons.

"I believe that we lost critical time in dealing with Iran because the White House chose to downplay the threats and chose to outsource the negotiations," Clinton said.

Earlier this week, a meeting in London produced no agreement among the U.S., France, Britain, Germany, Russia and China on whether to refer the dispute over Iranian nuclear enrichment to the Security Council, which could impose sanctions.

Russia and China have joined Europe and the U.S. in criticizing Iran's resumption of uranium enrichment. But both would prefer to avoid Security Council involvement and are outright opposed to sanctions, which are backed by the Bush administration.

While Clinton was critical of the administration, she never mentioned the president by name and did not engage in the same sort of sharp rhetorical attack against him or other Republicans as she did earlier this week.

Speaking Monday at a Martin Luther King Jr. memorial event in Harlem, Clinton said that the House of Representatives "has been run like a plantation" and called the Bush administration "one of the worst that has ever governed our country." The senator's remarks spurred heated reaction from Republicans.

Clinton spoke Wednesday to some 800 Princeton students, staff and alumni at the Woodrow Wilson School of Public and International Affairs.