Sudanese security agents confiscated an entire edition of the independent al-Tayar newspaper on Monday, its editor said, in the latest crackdown on media in the African country.

Sudan's constitution guarantees press freedom but journalists have complained of increasing pressure, particularly since the politically sensitive secession of South Sudan in July.

Security agents arrived after midnight at the newspaper's Khartoum offices and seized the entire Monday edition after it had been printed, editor Osman Murghni told Reuters.

Sudan's security service could not be reached immediately for comment.

Murghni said he was given no explanation for the raid, but added the paper's recent coverage of official corruption may have angered authorities.

The newspaper was the only local Arabic daily to report on accusations by Islamist opposition leader Hassan al-Turabi on Sunday that security services had bugged his office. Al-Tayar is close to the country's Islamist movement.

Around 20 reporters of the paper protested on Monday against the confiscation in front of the National Press Council which is in charge of licensing newspapers.

"Al-Tayar has not collapsed yet," read one banner.

Security forces have closed down two Islamist newspapers - Alwan and al-Rai al-Shaab - since the start of the year, according to editors.

Sudanese journalists say they face pressure when reporting sensitive issues such as corruption or the severe economic crisis Sudan is undergoing.

One day before the independence of South Sudan, Khartoum suspended six newspapers because southerners were among their publishers or owners.