The US is not looking to ease sanctions on Iran “at the front end” of negotiations over its nuclear program, a senior White House official said late Thursday.

“We are not contemplating anything that removes those sanctions at the front end of any negotiation or agreement, because it’s going to be important to test Iranian intentions,” said Ben Rhodes, President Barack Obama’s deputy national security adviser, at a conference hosted by Reuters in Washington.

“Before we could pursue sanctions relief, we’d have to see concrete steps by the Iranians to get at the state of their nuclear program,” he added.

The P5+1 powers — the five permanent Security Council members and Germany — held the first round of talks with Iranian negotiators earlier this month. The next round is scheduled for November 7 and 8 in Geneva.

Rhodes stressed that the Obama administration was looking for “flexibility” from Congress on pursuing talks without added sanctions — a move Congress has been poised to make.

“We continue to want to have that flexibility to pursue this diplomatic track. There’s an opening that we want to test,” Rhodes said.

“That doesn’t mean that Congress won’t consider new sanctions. It means that as they do, they should take into account the progress we’re making on diplomacy, and that we need to have some flexibility to pursue an agreement,” he added.

The US and Israel have been somewhat at odds over the issue of increased sanctions on Iran, with Prime Minister Benjamin Netanyahu pushing for added pressure on Tehran and arguing that the sanctions are what brought Iran to the negotiating table in the first place, while some in the Obama administration have considered pulling back the economic pressure on the Islamic Republic.

Convinced Iran is pursuing nuclear weapons, Netanyahu believes the Iranians are trying to trick the West into easing economic sanctions while still pushing forward with their nuclear program. Iran insists its program is for peaceful purposes.

During talks in Geneva earlier this month, Iran reportedly offered to stop enriching uranium to 20 percent, and to convert the country’s current stockpile into fuel rods, in exchange for the lifting of crippling economic sanctions.

The proposed measures, along with more probing inspections by the International Atomic Energy Agency (IAEA), were meant to allay global fears and make sure that the Islamic Republic cannot quickly reach nuclear weapons capability.

An Iranian source, whom the report claimed had “proven reliable in the past,” said his country offered to allow full monitoring of the underground enrichment facility at Fordo, and to convert it to a research facility.

Iranian officials denied the report.

But on Wednesday, an Iranian member of parliament said Tehran had halted all enrichment of uranium up to 20 percent, a key international demand. Hossein Naqavi Hosseini, who sits on the country’s foreign affairs committee, told a parliamentary news site that Iran had all the 20% enriched uranium it needed for medical research.

Israel has asked the international community to push for zero enrichment on Iranian soil, saying that maintaining the capacity to enrich uranium, even to low levels, could allow Iran to quickly “break out” to a bomb.

Yoel Goldman contributed to this report.