Media organisations are renewing a call for the release of three al-Jazeera journalists who have been held for 100 days since being arrested in Egypt.
The trio, including former BBC reporter Peter Greste, went on trial in February, accused of spreading false news and aiding a terrorist group.
They deny the charges, labelled by al-Jazeera as "absurd".
The case has drawn widespread condemnation from international media and human rights groups.
The three journalists are among 20 people facing similar charges. Only eight are currently in custody, while the remaining 12 are being tried in absentia.
A fourth al-Jazeera reporter, Abdullah Elshamy, who works for the network's Arabic channel, has been detained since August but not charged.
Mr Elshamy is on hunger strike and his wife says his health is deteriorating.
Peter Greste, al-Jazeera's Egyptian-Canadian Cairo bureau chief Mohamed Adel Fahmy and a local Egyptian producer, Baher Mohamed, were seized in a raid on a Cairo hotel in December.
They are accused of having aided the Islamist Muslim Brotherhood organisation, which Egyptian authorities banned and declared a terrorist group last December.
In his last court appearance last week, Mr Greste said the allegations were "preposterous".
The three men share a cell in which they are confined for 23 hours a day. Relatives say they remain strong, but are being denied adequate access to their lawyers.
Calls for their release have come from the European Union and the United Nations, among others.
On Monday, journalists launched a Twitter campaign posting images of themselves with black tape over their mouths at #freejournalism to highlight the increasing threat against reporters around the world.
At the BBC headquarters in London, scores of staff gathered in solidarity and held a minute's silence, hands clasped over their mouths.
The Egyptian authorities have accused Qatar-based al-Jazeera of bias and being overtly sympathetic to the Muslim Brotherhood.
The case marks the first time journalists have been charged with terrorism-related offences in Egypt, amid fears of a media crackdown by the military-backed authorities.