CAIRO (AP) — Hundreds of demonstrators gathered in and around Sudan's capital on Tuesday, calling for the ouster of autocratic President Omar al-Bashir and marching in memorial for those killed in past protests against him, activists said.

Tuesday's demonstrations, called by unions and opposition activists, fell on the anniversary of the 2005 killing of protesters in Port Sudan during an earlier period of demonstrations against al-Bashir's long rule. Protests also took place there.

The latest rallies were the largest in several days, as Sudanese have taken to demonstrating in local squares and neighborhoods sometimes blocked off with cars or makeshift barricades. Police have fired tear gas and live rounds that have killed at least two dozens demonstrators.

Organizers announced seven processions in areas of Khartoum and its twin city of Omdurman, with demonstrators gathering at intersections shouting "just fall," and calling for a "people's revolution." Police fired tear gas in some areas to disperse the crowds, activists said.

"It may take months, but I'm confident we will succeed," said Reem, a 25-year-old housewife facing off against clouds of tear gas in Omdurman. "The demonstrations have revived unions and organized us... and mobilized villages as well," she said by telephone, asking that her last name not be used for fear of reprisal.

Videos distributed by activists showed festive rallies in Khartoum and more urgent chanting in Omdurman, where they say security forces used tear gas to repulse demonstrators approaching the parliament building. Activists spoke on condition of anonymity for fear of reprisals.

The opposition Umma Party said in a statement that security forces surrounded its building in Omdurman and arrested several employees. It denounced the move but said it would not be dissuaded from "working to overthrow the regime and build a new Sudan."

The current wave of protests began Dec. 19 in opposition to surging prices and a failing economy, but quickly shifted to calls for an end to al-Bashir's nearly three-decade rule.

A devaluation of the currency in October pushed up prices, but lifting state subsidies on bread last month proved to be the final stroke, sparking the unrest. A cash crunch also led to long lines at ATMs and limits on cash withdrawals. Similarly, a fuel shortage meant hours-long waits at gas stations.

Al-Bashir, who seized power in a military coup in 1989, insists that only elections, which he intends to run in, could bring change.