(Updates with White House, U.N. ambassador)

By Sue Pleming

WASHINGTON, Nov 15 (Reuters) - Iran continues to provide only "partial answers" on its nuclear program and Washington will push ahead with a third U.N. sanctions resolution against Tehran, the United States said on Thursday.

"Partial credit doesn't cut it," said State Department spokesman Sean McCormack when asked about a U.N. nuclear watchdog agency report on Iran's nuclear program.

"These are partial answers," he said of information Iran had given the International Atomic Energy Agency.

The report by the IAEA released on Thursday found while Iran had made important strides toward transparency about its nuclear activity, it had yet to resolve key outstanding questions.

The White House and its ambassador at the United Nations, Zalmay Khalilzad, said the United States would continue to work with its allies for a new round of U.N. sanctions against Tehran over its refusal to give up uranium enrichment.

"Unfortunately this report makes clear that Iran seems uninterested in working with the rest of the world and the current Iranian government continues to push the country deeper into isolation," White House spokeswoman Dana Perino said.

Perino said the IAEA's report indicated Iran continued to defy the international community as well as two unanimous U.N. Security Council resolutions demanding that it suspend uranium enrichment.

"We believe that Iran should be fully cooperating and not stringing along the IAEA during this process," she added.

The United States is spearheading attempts at the United Nations for more sanctions against Iran but China and Russia are reluctant to impose more punitive measures and Beijing, in particular, has been accused of dragging its feet.

Khalilzad said Iran was still working on important aspects related to its nuclear program, such as building a heavy water reactor and continuing to enrich uranium. The West accuses Iran of building an atomic bomb while Tehran argues its nuclear program is for peaceful power generation purposes.

"We believe that we need to move forward with another (sanctions) resolution," Khalilzad told reporters at the United Nations.

He conceded China, which has veto power at the U.N. Security Council, was sending "mixed" signals over its support for a new resolution.

"We expect and will seek Chinese cooperation," said Khalilzad. "I don't think China would want to be in a position to cause a failure of diplomacy to deal with this issue," he added. (Additional reporting by Tabassum Zakaria in Washington and Patrick Worsnip at the United Nations)

AlertNet news is provided by