The Reporters Without Borders group has criticised the US, Canada and five other countries for their "harassment" of Arabic station al-Jazeera.
Al-Jazeera claims to reach 35 million viewers
"We regret some governments have no hesitation in censoring al-Jazeera... to protect their political and diplomatic interests," the group said.
The media watchdog also accused some of the governments of threatening the channel and blocking broadcasts.
The other countries named were Algeria, Saudi Arabia, Iran, Iraq and Tunisia.
Broadcasts on the channel "aggravate some leaders since it gives airtime to their opponents and to viewers, and because it broaches political and social issues seen as taboo", the Paris-based group said in a news release.
'Intolerance of critics'
It cited the US accusation that the Qatari channel was stoking up anti-American feeling in its coverage in Iraq.
Canadian authorities were criticised for ordering the channel to be monitored 24 hours a day, and making distributors responsible for making sure "abusive comments" were edited out before broadcast.
The US accuses al-Jazeera of inciting hatred against it
The group highlighted the indefinite closure of the al-Jazeera bureau in Baghdad and its denunciation as a "terrorist channel" by one Iraqi minister.
The other countries were taken to task for blocking or censoring al-Jazeera broadcasts, or refusing access to its correspondents.
"These methods demonstrate intolerance of critics," said the RWB statement.
It also urged the US authorities to explain the reasons for its detention of al-Jazeera cameraman Sami al-Haj at the Guantanamo Bay prison camp, or to release him immediately.
Al-Jazeera claims at least 35 million viewers and has been dubbed the CNN of the Middle East.
It has rejected attacks from senior US officials, such as Defence Secretary Donald Rumsfeld and his deputy Paul Wolfowitz, that its Iraq coverage is biased and incites hatred.
"We are simple observers, and not actors," said al-Jazeera spokesman Jihad Ballout.
The channel added that it was committed to providing balanced coverage.