The seven-year jail terms handed out to three al-Jazeera journalists accused of supporting Egypt's Muslim Brotherhood have led to an international outcry.
US Secretary of State John Kerry described the sentences as "chilling and draconian".
James Harding, the BBC's Director of News, said it was an "act of intimidation against all journalists."
Peter Greste, Mohamed Fahmy and Baher Mohamed were convicted of spreading false news on Monday.
The trio had denied the charges and are expected to appeal against the verdict.
The White House said that jailing journalists because their reporting did not fit the government "narrative" was "a blow to democratic progress in Egypt".
Mr Kerry said he had called the Egyptian foreign minister immediately after the sentence, and that he discussed these cases with President Abdul Fattah al-Sisi on Sunday, during his visit to Cairo as part of a regional tour.
Mr Kerry added it was now critical for the Egyptian president to move quickly to address international concerns on this.
But Egypt's foreign ministry rejected criticism of the ruling and insisted there had been no government interference.
"[We] strongly reject any comment from a foreign party that casts doubt on the independence of the Egyptian judiciary and the justice of its verdicts," it said in a statement.
The BBC's Bethany Bell in Cairo says that while the case has been condemned around the world, it has been presented differently by the Egyptian media.
Al-Jazeera, which is based in Qatar, was banned from operating inside Egypt after being accused of broadcasting reports sympathetic to former President Mohammed Morsi and the Muslim Brotherhood. Al-Jazeera has consistently denied the allegations.
Human rights group Amnesty said the trial was a "vindictive farce" and part of the "ongoing row" between Egypt and Qatar, which backs the Muslim Brotherhood.
Philip Luther, the group's Middle East and North Africa director, said it was "a dark day for media freedom in Egypt, when journalists are being locked up and branded criminals or 'terrorists' simply for doing their job."
'It defies all logic'
Australian Foreign Minister Julie Bishop told reporters she was "bitterly disappointed" by the outcome. Greste, a former BBC journalist, is an Australian citizen.
"We are deeply dismayed that a sentence has been imposed and appalled at the severity of it," she added.
Peter Greste's brother Michael - who is in Cairo - said he had spoken to his parents in Australia by phone shortly after the verdict.
"It was a very difficult phone call to make. They're especially distraught and very upset by the decision. We're all very confused about the ruling that was made today. To us it defies all logic," he said.
"They just ruined a family,'' said Fahmy's brother, Adel, who attended the hearing, adding he had little faith in the system. "Everything is corrupt," he said.
Christian Fraser, BBC News, Cairo
Peter Greste has spent six months in a 4m (13ft) cell with his two al-Jazeera colleagues, locked down for 23 hours a day with only a small window for light. The Tora prison is a "hell hole" says Greste's brother, Michael. "But he is strong and he will survive."
That resilience was on show when the prisoners came into court. They waved at friends and family and hugged each other, hoping their ordeal was now ending.
The judge, wearing sunglasses, looked unmoved by the scores of cameras there to record the verdict. Last week he sentenced 14 people to death, including the father of one of the students now standing in the cage.
As he heard the verdict, Peter Greste punched the cage in frustration. Mohamed Fahmy screamed in defiance. "He needs surgery, he has done nothing wrong," his mother wailed. Fahmy spent the first few weeks of his detention sleeping on the floor with a dislocated shoulder.
Eleven defendants tried in absentia, including three foreign journalists, received 10-year sentences. Two of the journalists convicted in absentia are British.
British Prime Minister David Cameron said he was "completely appalled" and the UK Foreign Office has summoned the Egyptian ambassador over the guilty verdicts.
In a statement, al-Jazeera English's managing director Al Anstey said the sentence "defies logic, sense, and any semblance of justice".
UN human rights chief Navi Pillay said she was "shocked and alarmed" by the sentencing and accused Egypt's authorities of "crushing" the media.
Jeremy Bowen, BBC Middle East Editor, tweeted: "Disgraceful 7 year sentences handed down to Al Jazeera journalists in Cairo. Egyptian euphoria after Mubarak's fall feels a world away."
James Harding said that the BBC, alongside other broadcasters and news organisations, would be submitting a letter to President Sisi asking him to address "this injustice".
BBC News staff will be holding a one minute silent protest outside their New Broadcasting House offices on Tuesday at 09:41 BST (08:41 GMT), the time of Monday's verdict.