A court in Egypt has ordered the release on bail of two Al Jazeera journalists, at the start of their retrial on the charge of spreading false news to help a terrorist group.

Mohamed Fahmy and Baher Mohamed were imprisoned in June along with their Australian colleague, Peter Greste.

Egypt's top appeals court overturned their convictions last month.

Mr Greste was freed last week under a law allowing the deportation of foreign nationals to their home countries.

Mr Fahmy has given up his Egyptian citizenship to qualify for deportation to Canada, but Mr Mohamed has no foreign passport.

The journalists strenuously deny collaborating with the banned Muslim Brotherhood after the overthrow of President Mohammed Morsi by the military in 2013. They say they were jailed simply for reporting the news.

The first trial of the journalists was widely condemned internationally, and the Court of Cassation ruled on 1 January the the Cairo Criminal Court had been "hasty in pronouncing its verdict".

On Monday, the deputy head of the Court of Cassation, Judge Anwar Gabry, said prosecutors had failed to present conclusive evidence that the defendants helped the Brotherhood or promoted the group

He also said the trial had failed to investigate claims that the defendants had given testimony under duress, and as a result "the Court of Cassation is unable to show how right or wrong the verdict is".

Families of the journalists worry the process may not be fairer the second time around, reports the BBC's Orla Guerin in Cairo.

Mr Fahmy's relatives have described the retrial as their worst nightmare.