International media rights groups accused the Sri Lankan government on Saturday of unleashing attacks against journalists after a bitterly contested presidential election.
The Paris-based Reporters without Borders asked President Mahinda Rajapakse to end arrests and what it called intimidation of journalists working for privately owned as well as foreign media.
"This wave of post-election violence could cast a lasting stain on the start of President Rajapakse's second term and bodes ill for the political climate during the coming years," said the watchdog, also known as Reporters sans Frontieres (RSF).
It said a political reporter disappeared two days before the vote while another editor of an anti-government newspaper had been arrested.
RSF urged the government to deploy more police officers to the search for political reporter and cartoonist Prageeth Eknaligoda, who has been missing since January 24. His family has had no news of him since.
The government has also ordered the expulsion of a Swiss reporter covering the elections.
The New York-based Committee to Protect Journalists (CPJ) said it had received reports of government retribution against journalists who were seen to be siding with the opposition in the election.
"Given the ugly history of attacks on journalists in Sri Lanka, we call on President Rajapakse to ensure the safety of all journalists in Sri Lanka, and to use his new mandate to reverse the repressive trends of the past several years," said the CPJ's Asia programme coordinator Bob Dietz.
Dozens of Sri Lankan journalists are living in exile abroad because of the dangerous and sometimes deadly atmosphere for media workers in Sri Lanka, according to rights groups.
Official figures show nine journalists have been killed and another 27 assaulted in the past three years in Sri Lanka while activists say over a dozen journalists have been killed.
Human Rights Watch said it feared the latest attacks against the media in Sri Lanka were aimed at silencing critics ahead of parliamentary elections due shortly.
Tuesday's election result has been challenged by the defeated opposition candidate Sarath Fonseka, whose office was raided by police on Friday.