WASHINGTON (Reuters) - A debate is under way in the Trump administration about whether the United States should declare the Muslim Brotherhood a terrorist organization and subject it to U.S. sanctions, according to U.S. officials and people close to President Donald Trump’s transition team.

Egypt's deposed president Mohamed Mursi greets his lawyers and people from behind bars at a court wearing the red uniform of a prisoner sentenced to death, during his court appearance with Muslim Brotherhood members on the outskirts of Cairo, Egypt, June 21, 2015. REUTERS/Amr Abdallah Dalsh/File Photo

A faction led by Michael Flynn, Trump’s National Security Advisor, wants to add the Brotherhood to the State Department and U.S. Treasury lists of foreign terrorist organizations, the sources said.

“I know it has been discussed. I’m in favor of it,” said a Trump transition advisor, who declined to be named because of the sensitivity of the issue.

The advisor said Flynn’s team discussed adding the group to the U.S. list of terrorist groups but said it was ultimately unclear when or even if the administration ultimately would go ahead with such a move.

Other Trump advisors, as well as many veteran national security, diplomatic, law enforcement and intelligence officials argue the Brotherhood has evolved peacefully in some countries, according to officials and people close to Trump’s entourage.

They worry that a U.S. move to designate the entire Brotherhood a terrorist group would complicate relations with Turkey, a key American ally in the fight against Islamic State, and where the Islamist-rooted AKP Party that dominates the Turkish government of President Recep Tayyip Erdogan is in power. Tunisia’s Islamist Ennahda Party has also participated in democratic elections.

The Muslim Brotherhood in Egypt, the country’s oldest Islamist movement, was designated as a terrorist organization in that country in 2013.

It is not clear which faction within the U.S. administration has the upper hand, and Senator Ted Cruz and Representative Mario Diaz-Balart this month introduced legislation to add the Brotherhood to the terrorist list.

There was no immediate comment from the White House.

MIXED RECORD

Egypt, Saudi Arabia, the United Arab Emirates among others have designated the group on their terrorist lists, and Trump’s nominee for Secretary of State, Rex Tillerson, described the Brotherhood an “an agent of radical Islam”, during his Senate confirmation hearing.

U.S. criminal law prohibits people in the United States from knowingly providing “material support” to designated terrorist organizations, and members of such groups are banned from entering the United States.Some conservative and anti-Muslim activists have argued for years that the Brotherhood, which was founded in Egypt in 1928 and sought to establish a worldwide Islamic caliphate by peaceful means, has been a breeding ground for terrorists.

Some branches of the Brotherhood, including the Palestinian group Hamas, have engaged in anti-government violence and provoked violent government reactions. Ayman al-Zawahiri, the leader of al-Qaeda, was once a member of the Egyptian Muslim Brotherhood.

Other offshoots in Turkey and Tunisia have forsworn violence and come to power by democratic means. Muslim Brotherhood President Mohammed Mursi became Egypt’s first freely elected president in June 2012 in the aftermath of the ousting of long-time ruler Hosni Mubarak. An army takeover stripped Mursi of power in 2013 following mass protests against his rule. Hundreds of Islamists have since been killed and arrested.

Sisi and Trump spoke by phone this week and the two leaders discussed ways to boost the fight against terrorism and extremism.

A U.S. official who declined to be identified told Reuters there had been discussions at the State Department which looked at intelligence and information on the group in which it was thought “it would be difficult to justify legally, in terms of the Egyptian Muslim Brotherhood, to meet the criteria”.

“It’s one thing to say one group’s ideology has been used to influence a terrorist organization and another thing to say that this group is a terrorist organization,” said the U.S. official.

Following the Sept. 11, 2001, al Qaeda attacks on the United States, the George W. Bush administration launched investigations into the Brotherhood and related Islamist movements.

After years of investigations, however, the U.S. and other governments, including Switzerland’s, closed investigations of the Brotherhood leaders and financial group for lack of evidence, and removed most of the leaders from sanctions lists.

A British government review into Egypt’s outlawed Muslim Brotherhood published in December 2015 concluded that membership of or links to the political group should be considered a possible indicator of extremism but stopped short of recommending that it should be banned.