The United Nations has expressed concern about the "increasingly severe clampdown and physical attacks" on journalists in Egypt, singling out three Al Jazeera reporters held for more than a month.
In a statement released on Friday, the UN High Commissioner for Human Rights said the clampdown on the media by Egyptian authorities was hampering the ability of journalists to operate freely.
"In recent months, there have been numerous reports of harassment, detention and prosecution of national and international journalists as well as violent attacks, including several that led to injuries to reporters trying to cover last weekend’s third anniversary of the Egyptian revolution," said Rupert Colville, the commissioner's spokesman.
The UNHCR said it was concerned about the Egyptian Prosecutor-General's intention to bring to trial 16 local and three foreign journalists working for Al Jazeera, on charges including "aiding a terrorist group" and "harming the national interest."
Correspondent Peter Greste and producers Mohamed Fahmy and Baher Mohamed have been held in custody for more than a month without charge.
Human-rights groups say conditions for journalists in Egypt have become difficult since former Egyptian President Mohamed Morsi was removed in a coup on July 3, 2013.
The Committee to Protect Journalists (CPJ) said that Egypt, Syria and Iraq had become some of the deadliest countries for journalists to work in.
The U.N. statement said in recent months, there have been numerous reports of harassment, detention and prosecution of national and international journalists as well as violent attacks, including several that led to injuries to reporters.
It added that unconfirmed reports suggest that several journalists were wounded by live fire as well as rubber bullets last Saturday, some of which may have been fired by opponents of the government as well as by police and other government forces.
"This accentuates the difficult and increasingly dangerous environment for journalists trying to carry out their work in the country," the statement said.
"A video has also emerged which appears to show a police officer threatening a camera crew working for another TV station that, if they did not stop filming, he would tell bystanders they worked for Al Jazeera so that they would be attacked,” the statement said.
"If confirmed, this lends credence to allegations that the anti-Al Jazeera campaign in Egypt is, on occasion, amounting to incitement to violence."
Writing from his prison cell south of Cairo, Greste said the authorities routinely violate legally enshrined prisoners' rights, denying visits from lawyers, keeping cells locked for 20 hours a day.
"But even that is relatively benign compared to the conditions my colleagues are being held in," he wrote.
Al Jazeera and news services