President Joe Biden has finally decided to keep Iran's Islamic Revolutionary Guard Corps on the black list of terrorists, further complicating international efforts to restore the 2015 Iran nuclear deal.

Biden announced his decision during an April 24 phone call with Israeli Prime Minister Naftali Bennett, Politico reported, citing a source, adding that the decision was handed over as absolutely final and the window for Iranian concessions was closed.

Bennett later confirmed the content of his conversation with Biden.

The United States placed the IRGC on its list of foreign terrorist organizations in 2019. It was part of the maximum pressure campaign that then-President Donald Trump imposed against Iran after the United States withdrew from the nuclear deal.

Biden administration officials have spent more than a year in often indirect discussions with European, Iranian and other officials aimed at resurrecting the nuclear deal. But while the negotiations have made significant progress, the designation of the IRGC as a terrorist has become a major stumbling block on the way to the final restoration of the agreement.

Iranian officials want the United States to remove the label of terrorism from the IRGC before Tehran returns to compliance with the nuclear deal. But the United States has refused to do so unless Iran makes any security-related concessions other than a nuclear deal.

Biden administration officials have signaled in recent weeks that they are increasingly reluctant to even consider revoking terrorist status, especially as both Democratic and Republican lawmakers warn against it.

The official made it clear that the administration's stance would not change, especially given the ongoing threats from the IRGC to the Americans.

Some advocates for restoring the 2015 agreement note that the designation of the IRGC on the Foreign Terrorist Organization list did not have a significant impact on US policy towards Iran, as the IRGC was already under many other sanctions, and believe that the decision is worth reversing in order to restore the nuclear deal.

But opponents of the nuclear deal point out that the IRGC poses a threat to much of the Middle East and a serious threat to Israel as well as the United States.