In a sudden move, Canada's top envoy to Sudan was expelled for "meddling in its affairs," the state news agency SUNA reported yesterday.

Chargé d'affaires Nuala Lawlor, and her European Union counterpart, were each declared persona non-grata. Sudanese foreign ministry spokesperson, Ali Al Sadeq, was quoted by SUNA as saying both diplomats were "involved in activities that constitute an intervention into the internal affairs of the Sudan, a matter that contradicts their diplomatic duties and mission."

Further details on the allegations have not been released. It was unclear whether the jargon implied spying activities or criticism of the Sudanese government's role in the country's ravaged Darfur region.

Diplomats in Khartoum said both missions had been working on human rights issues.

In Ottawa, a spokesperson for the foreign affairs department, Rodney Moore, was unable to provide details of what Lawlor was accused of.

But he said: "Ms Lawlor, in the finest traditions of Canadian diplomacy, was standing up for our values of freedom, democracy, human rights and the rule of law in Sudan. We have asked the Sudanese authorities why they have expelled her."

The EU Commission confirmed yesterday its ambassador, Kent Degerfelt, had been ordered out.

Degerfelt was on holiday in Italy at the time.

"I have been in Sudan for five years and I have always worked for the good of Sudan and its people and that is why I believe that maybe there is some sort of misunderstanding somewhere," he said.

David Kilgour, Canada's former secretary of state for Africa, said he was not surprised by the expulsions.

"It's entirely consistent with the other actions of the Sudanese government," he said.

The head of the UN mission in Sudan, Jan Pronk, was expelled in October for comments he made on his blog.

"They're a rogue regime that has continued to act in a predictable way – that is, completely unreasonably," Kilgour said.

The Sudanese government is trying to keep their "genocidal agenda" alive, he added.

Aurel Braun, a professor of international relations at the University of Toronto, said the move is consistent with Sudan's habitually harsh reaction to criticism. It's "part of a pattern to deter or frighten others from speaking up."

Calling the act "defiant," he said it was a show of strength on the part of Sudan towards the international community. "The Sudanese government is saying we don't care how clean you are, how fair you are, we can still expel you."

He called for Ottawa to take action by speaking out at the UN, moving for sanctions against Sudan or a tit-for-tat expulsion of Sudanese diplomats.

More than 200,000 people have died in the war-torn Darfur region since 2003.