Egypt's general prosecutor on Thursday charged 40 people with attempting to overthrow the regime, as massive anti-government demonstrations entered a third day. Protesters gathered in the eastern city of Suez early Thursday morning torched a police post, to decry killing of demonstrators earlier this week. At least four people, three protesters and a security official, have been killed since the clashes began on Tuesday. Protesters in Suez had the day before set fire to a government building and another police post on fire, as well as trying to burn down a local office of Egypt's ruling party. Those fires were all put out before they engulfed the buildings. A Reuters witness said police fled the post that was burned on Thursday before the protesters hurled petrol bombs. Dozens more protesters gathered in front of the second police post later on Thursday morning demanding the release of their relatives who were detained in protests. Demonstrations demanding the resignation of President Hosni Mubarak, in power since 1981, have raged since Tuesday across several cities, including Cairo and Suez. Officials say hundreds of people have been arrested. All three protesters killed in demonstrations to date were in Suez. The policeman was killed in Cairo. Meanwhile, thousands of demonstrators took to the streets of Yemen's capital city on Thursday to demand a change of government, inspired by the unrest that has ousted Tunisia's leader and spread to Egypt this week. At least 10,000 protesters gathered at Sanaa University and around 6,000 more elsewhere in Sanaa in protests organized by Yemen's opposition coalition, Reuters witnesses said. Police watched but no clashes were reported.