Iran has taken steps to control the flow of information from both domestic and international news sources, accusing them of exaggerating reports of anti-government protests in Tehran, the capital.
On Monday, the government ordered the expulsion of a Spanish television crew who were covering the protests against the re-election of Mahmoud Ahmadinejad, the Iranian president, one of the journalists said.
"We are the unwelcome witnesses," Yolanda Alvarez of the RTVE public broadcasting network said.
"They want to get rid of all the foreign media ... the streets last night were full of ant-riot police. The reason there has been no repression (until now) is definitely because they know we were there," she said.
Al Jazeera's Teymoor Nabili, reporting from Tehran, said that it had become increasingly difficult for the media to operate in Iran since the elections results were announced on Saturday.
"Day-by-day our ability to access any information has been slowly whittled away," he said.
"I now stand in a position where I am no longer allowed to take a camera out onto the streets, I am not even sure if I can walk out onto the streets with a mobile phone without getting into trouble.
Also on Monday, a reformist newspaper owned by Mir Hossein Mousavi, the defeated presidential candidate, was suspended by the authorities.
"It seems to be part of a pattern of behaviour by the Iranian authorities to limit the reporting of the aftermath of the disputed election"
BBC World Service director
According to a report in another newspaper, Mousavi's Kalameh Sabz
(Green Word) newspaper was suspended following the publication of an unspecified caricature, and a complaint concerning an insult to Ahmadinejad.
The paper's website reported that more than 10 million votes in Friday's election were missing national identification numbers, data which make the vote "untraceable."
However, it did not say where it got the information.
The British Broadcasting Company (BBC) said its broadcast was being electronically jammed causing service disruptions for viewers and listeners in Iran, the Middle East and Europe.
It said it had traced the jamming of the satellite signal broadcasting its Farsi-language service to a spot inside Iran.
"It seems to be part of a pattern of behaviour by the Iranian authorities to limit the reporting of the aftermath of the disputed election,'' Peter Horrocks, the director of BBC World Service in London, said.
Ahmadinejad lashed out at the media shortly after he claimed victory in the election that critics say was marked by widespread voter fraud.
The government increased its internet filtering. Social networking sites including Facebook and Twitter were not working, and mobile phone services were restored on Sunday, after being down on election day.
Geronimo Akerlund, a spokesman for the Swedish network SVT, said its reporter had been asked to "leave Iran as soon as possible", and Al Arabiya, the Dubai-based news network, said its correspondent in Tehran was verbally told by Iranian authorities that its office would be closed for a week.
At a news conference on Sunday, Ahmadinejad sought to allay fears about a media crackdown and said: "Don't worry about freedom in Iran. Newspapers come and go and reappear. Don't worry about it."