* Many papers self censor fearing legal cases
* Papers penalised financially for reporting
* Activist Eshaq said gang raped by security forces
KHARTOUM, March 19 (Reuters) - Sudan's security forces have charged three journalists with defamation and publishing lies for writing about a woman who said she was raped, the latest in a wave of press harassment in the war-torn African state.
Youth activist Safiya Eshaq told Reuters she was abducted, beaten and gang raped by plainclothes security men on Feb. 13 after anti-government protests, prompting a public outcry in the conservative Muslim society.
Eshaq fled Khartoum fearing for her life after she spoke out. A source in the security services said her medical and police reports were faked and denied any rape.
Security services this month brought charges of defamation and publishing false information against three journalists who demanded an investigation into the rape, a move the reporters said was aimed at intimidating the media into silence.
"They want to scare people to terrorise the journalists so they don't write about their abuses," said Amal Habbani, who told Reuters on Saturday her paper -- al-Jareeda -- had sacked her fearing retribution from the security services.
"(The government) say they want to move towards democracy so holding an investigation would make them look good," she said, adding she no longer had a lawyer after being sacked.
Sudan's constitution guarantees freedom of expression but laws granting wide-ranging powers to authorities are often employed against the Sudanese press.
Journalist Faysal Mohamed Saleh said the charges against them under the media law and the criminal code were punishable by a prison sentence and/or a hefty fine.
"They want to scare us and the papers so no one wants to publish anymore and actually no one has written about this since," he said, adding that charges were brought against him and his paper al-Akhbar.
Faiz al-Silaik, deputy chief editor of the opposition Ajras al-Huriya paper, was also charged in the latest of a string of court cases against the daily, which is linked to south Sudan's ruling party. He was unavailable to comment on Saturday.
Media freedom campaign group Reporters Without Borders (RSF) condemned the summoning of the journalists, accusing the judiciary of collusion with the security services.
"This is yet another example of a determination to gag the press and curb free expression," RSF Secretary-General Jean-Francois Julliard said in a statement.
"Nothing should be allowed to prevent the media from covering human rights violations in Sudan, which continue to be extremely worrying."
The security service used to censor content in papers' offices before publication. While these restrictions have been lifted, legal cases and the threat of financial punishments with a loss of advertising from government companies have encouraged self-censorship, ensuring sensitive topics are rarely discussed.
Khartoum has jailed dozens of activists and journalists without charges this year, hoping to stem small anti-government protests inspired by uprisings in neighbouring Egypt and Libya.
(Reporting by Opheera McDoom, editing by Paul Taylor)