Egypt deported three Al Jazeera journalists on Sunday, days after the Qatari-owned channel carried appeals from leaders of ousted President Mohamed Mursi's Muslim Brotherhood to stage protests against the army-backed government.

The Gulf emirate was a strong financial backer of Brotherhood rule and vehemently opposes the army's overthrow of Mursi and the ensuing bloody crackdown on his movement.

Al Jazeera's offices in Cairo have been closed since July 3, when they were raided by security forces hours after Mursi was toppled, although the channel, broadcast from Qatar, can still be seen in Egypt.

Security officials at Cairo airport, declining to be named, said Wayne Hay, Adil Bradlow and Russ Finn had been put on an Egyptian plane headed for London, after being forced to leave their equipment behind.

The men had been held since Tuesday. An Al Jazeera spokesman said they had been released and left Egypt without being given a reason for their detention.

The station also said that Shihab Elddin Shaarawi, an executive producer for Al Jazeera's Egyptian channel, had been arrested on Friday morning but later released.

The channel's cameraman Mohamed Badr was detained a month ago and Al Jazeera Arabic correspondent Abdullah Al-Shami was arrested on August 14.

Both are still in detention, but producer Mohammed Baher was freed on Sunday after being held for five days.

Last week, Al Jazeera aired statements from two Brotherhood leaders who had eluded a wave of arrests, Mohamed El-Beltagi and Essam El-Erian, that included a call to join protests against Egypt's military-backed interim government. Beltagi has since been caught.

"There has ... been a campaign against Al Jazeera in particular, as the channel's offices were raided last month and security forces seized equipment which has yet to be returned," Al Jazeera's English service said on its website.

The New York-based Committee to Protect Journalists said Egypt's government was widening a "censorship campaign", adding that its research showed that four other journalists were in custody.

"Egyptian security forces continue to detain and harass journalists working for news outlets critical of the military-led government, particularly Al Jazeera and its affiliates," it said last week.

On Thursday, the government said that Al Jazeera Mubashir Misr, the broadcaster's Egyptian channel, was operating without a licence and that unspecified legal measures would follow, "given the threat it poses to national security".

Ayman Gaballah, the head of the channel, said the accusations were fabricated. - Reuters