An Internet watchdog on Tuesday accused Ethiopia of blocking scores of anti-government Web sites and millions of Weblogs in one of sub-Saharan Africa’s biggest cases of cyber-censorship.

Web monitor, the OpenNet Initiative, said the Horn of Africa country was stopping citizens from viewing opposition-linked Web sites, and blogs hosted by Blogger, an online journal community owned by Internet search engine Google Inc.

Ethiopia dismissed the report as “a baseless allegation”.

“We may have technical problems from time to time,” Information Ministry spokesman Zemedkun Tekle. “But we have not done anything like that and we have no intention of doing anything like that.”

The OpenNet Initiative — a partnership between Harvard Law School, and universities of Toronto and Cambridge and Oxford — said it had gathered proof of interference.

“We have run diagnostic tests using volunteers in Ethiopia which indicate that they are blocking IP addresses,” OpenNet research director Robert Faris said, referring to the unique numeric addresses of Web sites.

“The evidence is overwhelming that that is what they are doing. … Most of the sites that we found blocked were related to freedom of expression, human rights and political opposition,” he said by telephone from the United States.

The allegations could be embarrassing for the Ethiopian government, which is a major ally of the United States in Africa and has been criticised for a post-election crackdown on opposition that killed nearly 200 people in 2005.

“I think it’s a decision that makes the Ethiopian government look extremely hostile to free speech and to open political discourse,” said Ethan Zuckerman, research fellow at the Berkman Center for Internet and Society in the United States.

The Ethiopian blockages are part of a growing global trend, Faris said.

“As recently as five years ago, China, Iran and Saudi Arabia were the only countries that were filtering the Internet. Now we have found two dozen,” he added.

The full list of countries will be published in a book later in the year titled ‘Access Denied: the Practice and Policy of Global Internet Filtering’ published by the Massachusetts Institute of Technology Press. Part of an initial report on the findings, that will be presented at a conference in Cambridge later this month, has been seen by Reuters.

OpenNet found some filtering of pornographic and political Web sites in Islamic North African countries including Tunisia.

Some pornographic and anti-Islamic sites were also blocked in Sudan, although the Web sites of many human rights groups critical of the situation in Darfur remained visible.

But it found no evidence to back up reports of online censorship in Eritrea and Zimbabwe. Ethiopia was the only widespread campaign identified in sub-Saharan Africa, the OpenNet report said.

“We are very interested in Ethiopia because it is a very recent entry into this field. Its internet penetration is very low but it is still going to the trouble of blocking the internet. That shows the lengths that the regime is willing to go to,” said Faris.

Ethiopia has one of the world’s lowest Internet access rates — only two out of every thousand Ethiopians were logging on in 2003, according to the United Nations Development Programme’s latest Human Development Report.

But it also has one of Africa’s healthiest blogging scenes, fuelled by a handful of anonymous writers in the capital Addis Ababa and the large communities of politically active Ethiopians in the United States and Europe.

Bloggers like Nazret.com (http://nazret.com/blog) published the first eyewitness accounts of political unrest that followed controversial national elections in 2005. Resident bloggers including Seminawork (http://seminawork.blogspot.com) have provided daily updates of the ongoing trial of opposition politicians. Ethiopundit (http://ethiopundit.blogspot.com) and Carpe Diem Ethiopia (http://carpediemethiopia.blogspot.com) are among a long list of Diaspora bloggers well known for their scathing political commentary.

Ethiopian bloggers have started displaying ‘Blocked in Ethiopia’ badges on their websites and swapping technical tips on how to get round the filters. Other sites currently inaccessible in Ethiopia include the home page for the opposition Coalition for Unity and Democracy (http://www.kinijit.org) and 39 out of the 61 Ethiopian weblogs tracked by GlobalVoices, a website that reports on weblogs outside the West part-funded by Reuters.

OpenNet said many of the sites were caught in a blanket blockage of blogs hosted by Google’s Blogger service, home to many millions of blogs across the world, most of them nothing to do with politics.

OpenNet said it found evidence of the blockage by recruiting volunteers who ran programs on their computers inside Ethiopia scanning the network run by the state monopoly provider Ethiopian Telecommunications Corporation. The results were then emailed back to OpenNet for analysis.

The scans followed the individual units or “packets” of digital data that get sent out whenever an internet user types a web address into a browser’s address box. “We found that the packets were dropped at the same place… Any packet associated with a particular IP address was dropped. You get a ‘time out’ message when you try to access the site. Your request never leaves the country…It is the simplest and bluntest way of blocking,” said Mr Faris.