Egypt's interim president has said Al Jazeera English's journalist, Mohamed Fahmy, will be given the "best treatment possible" for a fractured upper arm he suffered more than three months ago.

Fahmy's family received a letter from Adly Mansour on Sunday in response to their pleas to help Fahmy, who has been in prison with the injury since December after being arrested along with two colleagues for "spreading false news".

Mansour said he instructed the interior minister to follow up on Fahmy's medical condition and provide "the best treatment possible". He was taken to hospital on Sunday for tests, the results of which are expected on Monday.

"I want to reaffirm in this regard the independence of the Egyptian judiciary and my confidence that your son will get all his legal rights," Mansour added.

The note was a response to a letter from Fahmy's family, which said he had received little medical attention while in jail, and that his condition had worsened.

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"He can't lift his arm except 20cm," said Fahmy's brother, Adel, who added that he thought the president's letter was a good sign.

The trial of Al Jazeera's journalists, Peter Greste, Baher Mohamed and Fahmy will resume on Monday.

They are accused of "spreading false news" and "belonging to a terrorist group" after reporting on the military's removal of the Muslim Brotherhood's Mohamed Morsi from the presidency last year.

Al Jazeera strongly rejects the charges, and calls for the immediate release of its journalists. Fahmy has also been accused of being a member of the Brotherhood, a charge that he denies.

Source: Al Jazeera and agencies