Sudanese police fired tear gas at protesters on Friday as they took to the streets after midday prayers to chant anti-government slogans in the capital’s twin city of Omdurman, witnesses said.Anti-government rallies have rocked cities across Sudan since December 19 when protests first broke out over a government decision to raise the price of bread.Protesters chanting “freedom, peace and justice” poured out of a mosque in Omdurman, parallel to Khartoum on the west bank of the Nile, witnesses said.But they were swiftly confronted by police who fired tear gas to disperse them, witnesses said.