KHARTOUM - Sudanese security forces have arrested opposition leader Hassan al-Turabi and eight other party officials after they called for a "popular revolution" if Khartoum did not reverse price rises

Turabi's arrest on Monday comes at a politically sensitive time for the government of President Omar al Bashir, who stands to lose control over the oil-producing south, which last week voted in an independence referendum.

It also comes as Tunisia grapples with fallout from the ouster of long-time President Zine al-Abidine Ben Ali, who fled the country on Friday after three weeks of violent unrest sparked by social grievances.

Sudan's opposition threatened on Sunday to take to the streets if the government did not remove its finance minister and dismantle parliament over the decision to raise prices on a variety of goods.

"This is criminal - how can they arrest a man who is 78 years old and put him in prison? We are scared for him," Turabi's tearful wife, Wisal al-Mahdi, said.

Ben Ali's overthrow has reverberated across the Arab world, raising concerns about stability in the region.

Sudan's price increases have sparked student protests in the country's northern agricultural heartland and in Khartoum.

The country is grappling with a current account deficit and a currency devaluation that is driving up inflation.