The White House has confirmed it is considering the designation of the Muslim Brotherhood as a terrorist organisation, after Donald Trump was personally lobbied by Egypt’s president, Abdel Fatah al-Sisi.

The official designation of the Islamist movement as terrorist would have far-reaching effects, sanctioning companies and individuals who had any interactions with the group.

Such a move has been considered before, most recently by the Trump administration soon after taking office, but had been rejected as being impractical for such a diffuse and multifaceted organisation, and potentially illegal under US law.

However, the White House spokeswoman, Sarah Sanders, said on Tuesday: “The president has consulted with his national security team and leaders in the region who share his concern, and this designation is working its way through the internal process.”

The order to look again at the designation, first reported by the New York Times, came in the wake of Sisi’s visit to the White House on 9 April.

Sisi – whose support Trump is seeking for the launch of a Israeli-Palestinian peace plan championed by his son-in-law, Jared Kushner – succeeded in winning over the US president on two issues: expressing support for the Libyan warlord, Khalifa Haftar, and reviewing the possibility of designating the Muslim Brotherhood as terrorist.

The Muslim Brotherhood is a network of loosely affiliated groups across the Islamic world. In Egypt, the movement has gone underground since Sisi took power, but remains a source of determined opposition to his regime.

The White House portrayed the step as being in its early stages, but reflecting the sort of bold action the administration took earlier this month to designate the Iranian Islamic Revolutionary Guard as a foreign terrorist organisation.

“The president has heard the concerns about the Muslim Brotherhood from our friends and allies in the Middle East, as well as here at home. Any potential designation would go through a robust, deliberate and inclusive interagency process,” a senior administration official said.

Daniel Benjamin, a former counter-terrorism coordinator at the state department said: “State looked at this in 2017-18 and concluded there was no legal basis for designation. That continues to be true.”

Benjamin, now director of the centre for international understanding at Dartmouth College, went on: “If it ever went to court the administration would be risking serious embarrassment. The administration would have a hard time showing the Brotherhood would meet any of the historic standards associated with designation of a foreign terrorist organisation.”

He pointed out that the Egyptian branch of the movement forswore violence in the 1970s.

“If anything, the Muslim Brotherhood has come in for tremendous criticism from al-Qaida, for supporting democratic elections and deviating from the path of violence,” Benjamin said.

If implemented, the move risks skewing US foreign policy towards a number of allies that contain parties or organisations aligned with the Muslim Brotherhood, including Tunisia, Iraq, Kuwait, Jordan and Turkey. Affiliates of the group are also present in Syria and in Libya, where it is part of the unity government endorsed by the United Nations, the Government of National Accord.

“Trump is trying to lead the region into disaster,” said Amr Darrag, a former prominent member of the Muslim Brotherhood and minister in the Islamist government of Mohammed Morsi, overthrown in the 2013 military coup which brought Egypt’s Sisi to power.

“This is a mess,” said Darrag. “All of this just to please Sisi.”

Darrag fears that the designation could radicalise young supporters of the Brotherhood. “If this designation happens now, it will give Isis and al-Qaida further evidence to present to young people, saying that you’ve been labelled terrorists so what are you waiting for, why don’t you become real terrorists,” he said. “This could turn the region into chaos. Imagine the repercussions of something like this.”

The United Kingdom conducted a review of the Muslim Brotherhood under David Cameron’s leadership in 2015, examining the group’s origins and ideology in order to judge whether it had links to extremists. The review found that “for the most part, the Muslim Brotherhood have preferred non-violent incremental change,” and the group was primarily committed to political rather than violent engagement.

Michele Dunne of the Carnegie Endowment for International Peace said that such a decision would be “an extremely imprudent step” given that the organisation does not fit the legal criteria for a foreign terrorist organisation.

“This decision could have very unpredictable implications,” she said. “It could be used to curb the civil liberties of US citizens who are Muslims. I find this deeply troubling.”