|Turabi was arrested on January 18, and is routinely picked up for anti-government remarks [EPA]
Hassan al-Turabi, Sudan's Islamist opposition leader, has called for a "total political system change" in the country, hours after being released from jail.
He was detained for more than three months after he called for a popular revolution.
Speaking at his house in Khartoum on Monday, Turabi said while Sudan may not see an uprising similar to Tunisia and Egypt, it nevertheless needed major changes.
"We want a total political system change, a democracy in Sudan. A real change, not just dialogue ... which we tried before," Turabi said.
"A revolution can lead to chaos in Sudan because Sudan is decentralised and tribalised. We need to organise a transition for change," he said.
"I call for the Sudanese people to start their own revolution against corruption, because there are revolutions in many Arab countries and the Sudanese people are not less than the people of those countries," he said. "The situation in Sudan is worse than in those countries."
Security forces had arrested Turabi and eight other Popular Congress Party officials on January 18 after he had called for a popular revolution if the government did not rein in inflation.
His comments came a politically sensitive time for Omar al-Bashir, the Sudanese president, as the south of the country is poised to break away after voting for independence in a referendum in January.
Turabi has been in and out of jail since splitting from Bashir's ruling party in 1999/2000. He was the spiritual mentor of Bashir's Islamist government when it took over after a 1989 coup.
Remarks on Bin Laden
Turabi was also reportedly close to Osama bin Laden, the al-Qaeda leader who was shot and killed by US forces in a raid on Sunday night.
"All Muslims are sad today. I don't like the killing of any human," he told reporters.
"Osama bin Laden had some good intentions but that does not mean I approve everything he did," he said, describing the attacks on the United States on September 11, 2001, as a mistake.
Regarding his own detention, Turabi said that no charges had been laid against him.
"No one told me why they arrested me and no one told me why I was released," he said.
Under Sudanese law, security forces are allowed to hold people for up to 45 days without charging them.