The United States has accused Iran of stalling while it continues to pursue suspect technology, but Tehran accused Washington on Thursday of putting up "obstacles."

The Iranian council said special committees in key state agencies were still studying the offer by the United States, Britain, China, France, Russia and Germany, and it invited the United States and its allies to return to the negotiating table.

It said it was "surprising" that the United States was creating obstacles for a negotiated settlement while Iran was seriously studying the offer.

"Iran is not after tension, but if others push things toward tension and create problems, then all will face problems. Iran believes dialogue is the most logical solution. It is serious in this path. We want the other side to return to the negotiating table," the statement said.

"The Islamic Republic of Iran is committed to a negotiated settlement through diplomacy. The United States, by changing the path of talks toward the Security Council, is trying to create obstacles."

A senior Iranian lawmaker said Tuesday the country's parliament was preparing to debate withdrawal from the nonproliferation treaty if the UN Security Council adopts a resolution that would force Tehran to suspend uranium enrichment.

Withdrawal from the treaty could end all international oversight of Iran's nuclear program.

In February, Iran for the first time produced its first batch of low-enriched uranium, using a cascade of 164 centrifuges. The process of uranium enrichment can be used to generate electricity or in building a bomb, depending on the level of enrichment.

Iran has said it will never give up its right under the treaty to enrich uranium and produce nuclear fuel, but it has indicated it may temporarily suspend large-scale activities to ease tensions.