The US National Security Council on Thursday hosted top staffers from congressional committees dealing with Iran sanctions at a White House briefing.

The Obama administration is weighing whether to offer Iran the chance to recoup billions of dollars in frozen overseas assets if it takes steps to scale back its nuclear program, US officials and congressional aides said Friday.

The proposal would face a skeptical Congress determined to make the end of Tehran's uranium enrichment activity the condition for any sanctions relief.

The aide said Republicans would resist further delay, but that the decision was in the hands of Democratic Senator Tim Johnson, the committee's chairman, and Senate Majority Leader Harry Reid, also a Democrat.

A Johnson spokesman confirmed that a meeting on Iran took place at the White House but gave no further details. A Reid spokesman was not immediately available to comment.

The Obama administration launched renewed talks this month with Iran in the wake of pledges from its newly elected president, Hassan Rouhani, to cooperate with major powers in making Iran’s nuclear program more transparent.

Obama administration officials have said sanctions will remain in place until Iran tangibly shows it is abiding by UN Security Council resolutions and suspending uranium enrichment, but Iran's new government says it wants to continue enriching uranium for civilian uses and declared it wouldn't ship nuclear materials out of the country.

Iran has repeatedly announced it wants nuclear energy for peaceful purposes under the supervision of the International Atomic Energy Agency (IAEA).

Some congressional leaders as well as Israeli Prime Minister Benjamin Netanyahu urge Washington to intensify existing sanctions as a means of increasing leverage over Iran.

However, US negotiators have said that such a move would be counterproductive.

NTJ/BA