In a statement, the movement said that it would "openly engage" with the review ordered by Prime Minister David Cameron but it would challenge in the British courts "any improper attempt to restrict its activity".

The Brotherhood, a movement whose affiliated groups have deep roots in many Arab and Islamic states, said it was concerned that Britain's ambassador to Saudi Arabia, John Jenkins, would be leading the review, the statement issued late on Wednesday said.

Saudi Arabia, a commercial ally of Britain and staunch foe of the Brotherhood, designated the group a terrorist organization last month following a similar move by Egypt in December.

"It is important that the British government does not bend to pressure from foreign governments who are concerned about their own people's quest for democracy," the statement released by the Brotherhood's press office in London said.

"It is hard to see how Sir John Jenkins will be able to conduct an independent internal review of the Muslim Brotherhood and carry his brief as Ambassador to a non-democratic regime that is openly in political opposition to the Muslim Brotherhood."

Riyadh has given the Egyptian army, which deposed Islamist President Mohammad Morsi last year after mass protests against his rule, billions of dollars to support the beleaguered economy.

When asked why Jenkins was leading the review, a spokeswoman for Cameron said on Tuesday it was because it would focus on the group across the region, not just Egypt, and Jenkins had deep knowledge of the Middle East.

The Brotherhood gained political power in some Arab nations after the 2011 uprisings that toppled autocratic rulers. But the group has since been crushed in Egypt after the military overthrew Morsi in July and been subjected to a wave of prosecutions and jailing.

Britain, where many Brotherhood-influenced organizations are based, said its review would include looking at allegations made by Arab leaders that the group was linked to violence, a charge it has repeatedly denied.

NJF/NJF