Sudanese police fired tear gas after hundreds of protesters spilling out of a soccer match marched down a major road leading towards the center of the capital, Khartoum, late on Sunday, demonstrating against President Omar al-Bashir's rule, a Reuters witness said.Amid a heavy police presence, the protesters gathered in Omdurman, just across the River Nile from central Khartoum, and chanted, "The people want the fall of the regime" and "Freedom! Freedom!."About 4km (2.5 miles) from the stadium, security units, including elite forces, prevented them from crossing a bridge that leads towards the heart of the capital and the presidential palace.Cities across Sudan have been shaken by five days of protests over price rises, shortages of basic commodities and a cash crisis. Protesters have repeatedly targeted the offices of Bashir's party and called for an end to his 29-year rule.Since the demonstrations started spreading on Wednesday, police have dispersed protesters with tear gas as well as using live ammunition in some cases, residents say. Authorities have declared states of emergency and curfews in several states.Government officials have blamed the unrest on "infiltrators." Officials and witnesses have recorded at least 12 deaths, though exact casualty figures are hard to ascertain.After the soccer match on Sunday evening, security forces had cordoned off main streets around the stadium and more than 30 trucks carrying police in riot gear were spread across the area.When the match ended, fans marched down Al Arbaeen street in Omdurman singing and chanting until they got close to the river, where they were blocked by security forces, one witness told Reuters."They encircled them in four-wheel drives from the back and confronted them with vehicles coming from the White Nile bridge, forcing some of the protesters to enter the military hospital," he said.Earlier on Sunday in Um Rawaba in North Kordofan state, three people were wounded as police dispersed protesters, according to a witness in the southern town.Security forces had changed tactics by moving more quickly to break up protests as soon as they started, he said.Bashir, one of the longest-serving leaders in African and the Arab world, took power in an Islamist and military-backed coup in 1989.Members of parliament this month proposed a constitutional amendment to extend term limits that would have required him to step down in 2020.