Iran could collect up to $50 billion in oil revenue if sanctions are lifted, according to congressional officials briefed by the Obama administration.

If negotiators are successful in brokering a deal with Iran this summer to suspend its nuclear program, officials say the country could receive between $30 billion and $50 billion after signing an agreement, the Wall Street Journal reported.

Right now, Iran is estimated to have between $100 billion and $140 billion of its oil revenues frozen in offshore accounts due to economic sanctions linked to efforts to prevent the country from developing nuclear weapons. Details are still being negotiated, but Iran's cash flows would increase if it agrees to rules laid out by world leaders.

Major sticking points remain over how quickly to roll back the sanctions and how to reinstate them if Iran violates the perimeters of the agreement.

President Obama has previously backed phasing out the sanctions gradually. The White House said Friday that position hasn't changed, although the president didn't reaffirm that commitment in a press conference.

Instead, Obama appeared to open the door to allowing Iran to receive significant economic relief as soon as a final deal is signed. His main concern, he said, is to ensure the sanctions can be quickly put back in place should Iran violate the terms of the agreement.

"Our main concern here is making sure that if Iran doesn't abide by its agreement that we don't have to jump through a whole bunch of hoops in order to reinstate sanctions," Obama said. "It will require some creative negotiations."

Iranian leaders, including President Hassan Rouhani, have insisted they would only agree to a deal if it provides full and immediate relief from sanctions.

Congressional Republicans and Democrats alike are voicing strong opposition to removing the sanctions if a final deal negotiated by Obama with Iran matches what was outlined in the recently announced framework agreement.

The U.S. has been involved in enforcing sanctions against Iran since 1979, which makes it harder for the country to acquire the materials it would need to build nuclear weapons but also takes an economic toll on its citizens.

Under the agreement currently being negotiated by Iran and a coalition that includes all the U.N. Security Council nations and Germany, sanctions would be lifted for at least 10 years provided Iran abides by certain conditions.