Peter Greste: Egypt detention is 'attack on press freedom'
An Australian journalist, who is being held in an Egyptian jail with two colleagues, says their detention is an "attack on freedom of speech".
"We have not been formally charged, much less convicted of any crime," Peter Greste wrote in a letter.
The Al-Jazeera journalists were arrested on 30 December in Cairo for allegedly holding illegal meetings with the banned Muslim Brotherhood.
The Islamist group is facing a crackdown by the army-led government.
Mr Greste, a former BBC correspondent, sent his letter from Cairo's Tora prison, where he has spent a fortnight in solitary confinement.
"I've been locked in my cell 24 hours a day for the past 10 days, allowed out only for visits to the prosecutor for questioning," he writes.
The journalist said he had initially fought his imprisonment "quietly from within", in order to avoid losing access to books and his right to leave the "cold cell" for a short walk in the yard.
"I have sought, until now, to make the authorities understand that this is all a terrible mistake, that I've been caught in the middle of a political struggle that is not my own," he says.
"But after two weeks in prison it is now clear that this is a dangerous decision. It validates an attack not just on me and my two colleagues but on freedom of speech across Egypt."
The Interior Ministry accuses Mr Greste and fellow al-Jazeera journalists Mohamed Fahmy and Baher Mohamed of collaborating with terrorists and broadcasting false information.
But Mr Greste has rejected the allegations, stressing he had only been trying to report events with fairness, balance and accuracy.
He said the arrests sent a message to all journalists that authorities will not tolerate critical voices.
In December, authorities declared the Muslim Brotherhood a "terrorist organisation", blaming it for a string of attacks - claims the movement denies.
The military ousted the Brotherhood's Mohammed Morsi as Egyptian president last July.
Correspondents say the government has long accused the Qatar-based Al-Jazeera broadcaster of bias, because Qatar gave financial support to Mr Morsi's administration.
"The prisons are overflowing with anyone who opposes or challenges the government," he notes in his letter.
"So our arrest is not a mistake, and as a journalist this IS my battle."
Mr Greste also pointed out that his colleagues were being held in the "far more draconian Scorpion prison built for convicted terrorists", because they were accused of being Brotherhood members.
He added that the prosecutor general had extended the initial 15-day detention by another 15 days "to give investigators more time to find something".
"He can do this indefinitely - one of my prison mates has been behind bars for 6 months without a single charge," Mr Greste says.
Observers say Egypt's media environment has been highly charged since Mr Morsi's overthrow.
Several Islamist channels were closed down immediately after the military intervention last summer. Al-Jazeera's Egyptian station Mubashir Misr was shut down in September.
The channel previously had its Cairo offices raided, equipment seized, and staff detained.
Two of its staff - journalist Abdullah Elshamy and cameraman Mohammad Badr - arrested in July and August remain in detention, according to the Committee to Protect Journalists.