Sallah, a leading member of the opposition National Alliance for Democracy and Development and on the editorial board of the Foroyaa newspaper, was arrested Thursday, according to media sources who spoke on condition of anonymity.

Gambian security officers also visited the headquarters of the independent newspaper The Point on Friday morning.

They were looking for the paper's remaining editors but they were not present.

The arrests by the Gambian authorities, already strongly criticized for their human rights record, has sparked outrage from international media rights groups.

Reporters Without Borders (RSF) Friday expressed anger over what it called "a wave of repression" by the government.

"(President) Yahya Jammeh has shown his contempt for the media for years, but rarely has his message been so clear. He is determined to stifle all critical voices for good," the organisation said in a statement.

The New York-based Committee to Protect Journalists (CPJ) said they were deeply anguished by the arrests.

"President Jammeh is acting in a petty and vindictive manner and should be held personally accountable for his egregious abuse of power," CPJ director Joel Simon said in a press release.

The furore began when the Gambian Press Union (GPU) issued a statement this weekend criticising the president for "provocative" and "inappropriate" comments about the 2004 murder of veteran journalist Deyda Hydara.

Both Foroyaa and The Point had published the GPU statement.

With Sallah's arrest there are now nine journalists in custody. On Thursday seven were officially charged with sedition, defined as incitement to resistance against lawful authority.

Those charged are: Foroyaa editor-in-chief Sam Sarr, editor-in-chief of The Point Pap Saine, journalists and press union officials Emil Touray, Pa Modou Faal and Sarata Jabbi-Dibba, and journalists Ebrima Sawaneh and Abubacarr Saidykhan.

The men were all denied bail and taken to Banjul's notorious Mile Two prison. Jabbi-Dibba was granted police bail to allow her to nurse her six-month-old baby. However, she also remains in prison as her family has been unable to raise bail of 200,000 Dalasis (5,418 euros, 7,547 dollars).

Their next court hearing is on Monday.

The CJP says that before Pap Saine's arrest he was due to go to neighbouring Dakar for treatment on a heart condition.

On Thursday, security forces also arrested another The Point editor, Abba Gibba.

On June 8, Jammeh said in an interview on Gambian state television that the government had "no stake" in Hydara's killing. He hinted that the investigative journalist's love life had led to the murder.

Hydara, editor and co-founder of The Point and also AFP's Gambia correspondent, was gunned down by unidentified gunmen in his car on the outskirts of Banjul in December 2004.

Many observers suspect government involvement in the killing.

Jammeh, an outspoken military officer and former wrestler, has ruled the former British colony since seizing power in a bloodless coup in 1994.

He has made headlines in recent years by announcing he had found a herbal cure for HIV/AIDS and threatening to behead all gays in the Gambia.