The Trump administration is looking to put more pressure on Iran by carrying out more sanctions on its financial sector in order to further hamper its economy, sources with information on the issue disclosed Thursday.

The move is seen to essentially leave the Islamic republic choked off from the world's financial markets, cutting the few remaining connections it has and forcing the country to rely more on informal or even illegal trade.

The move comes after the U.S. said it forced a "snap back" last month of practically all sanctions the United Nations imposed on Tehran, a postulation denounced by major U.S. allies and most U.N. Security Council member nations, including China, Europe and Russia.

The U.S. has been analyzing the action for weeks and aims at 16 Iranian financial institutions for their participation in the government's financial sector - one bank for being controlled by another penalized Iranian bank, and one bank with ties to the armed forces, the U.S. Treasury disclosed in a statement.

Foreign firms that engage in business with the said banks were given 45 days to ease down their operations lest be subjected to "secondary sanctions," the sources said.

Based on reports, the measures would comprise two goals: shutter the few remaining financial conduits that enable Tehran to gain money, and impede Democrat presidential aspirant Joe Biden's pledge to revive a 2015 nuclear pact if he wins in the November U.S. elections.

Tensions between the U.S. and Iran have worsened since U.S. President Donald Trump single-handedly pulled out of the Iran nuclear agreement in 2018 and started implementing sanctions that had been toned down in the deal.

U.S. sanctions have dealt a heavy blow to Iran's economy. According to Iranian President Hassan Rouhani in June, his country experienced the most difficult year because of the U.S. financial pressure not to mention the global health crisis which has badly impacted the Islamic republic, Reuters reported.