The United States government is reportedly mulling to designate the Iranian Revolutionary Guard Corps (IRGC) and the Muslim Brotherhood as foreign terrorist organisations.
However, executive orders to enforce this decision have been put on hold as national security agencies are concerned about the consequences of such a move.
The move could however be only symbolic as Iran is already designated by the US as "state sponsor of terrorism" along with sanctions.
According to a CNN report, drafts of executive orders have been written and State Department has been asked to study potential designations of the groups. However, it was not clear when the orders would be passed, the report added.
Officials told the news organisation that the main concern over placing IRGC on a terrorist list was that it would place Iraqi Prime Minister Haider al-Abadi in a tough situation. Iraq is an important ally of the US in its fight against the Islamic State (Isis) and Iraqi forces also depend up on support from IRGC.
Iranian Revolutionary Guard was founded in 1979 after the Islamic revolution in Iran and is an elite military unit which reports directly to the supreme leader Ayotollah Ali Khamenei. It has a command separate from the traditional Iranian military.
Meanwhile, US allies in Egypt and United Arab Emirates have reportedly asked Trump to designate Muslim Brotherhood as a terrorist group. However, Career diplomats at the State Department and National Security Council have raised questions of the legal basis for a designation and voiced concern that it could potentially alienate allies in the region.
Egypt's Muslim Brotherhood was established in 1928 and is a social organisation that calls for the establishment of an Islamic society through democratic means.
The State Department's process of placing a group on the list of Foreign Terrorist Organisation is an arduous and time consuming one that takes several months. The Department conducts exhaustive research from US data bases and works with foreign governments to determine the threat posed by a group and then sends a proposal to other agencies like the Treasury and NSC for input before the lawyers from State Department conclude.