Manama--Protesters blocked a main thoroughfare to Bahrain Financial Harbour Sunday, a major business district in the Gulf Arab banking center, facing off with police who fired clouds of tear gas and water cannon. In one of the most violent confrontations since troops opened fire on protesters last month, youths erected barricades across the highway after overwhelming riot police near the Pearl roundabout, the focal point of weeks of demonstrations. "Investment in Bahrain is for everyone not just one person," said Ali, a protester at the Financial Harbour which has become a symbol of what protesters say are royal excesses. "That's why we have problems. It's not about Sunnis and Shias." One demonstrator showed a round red mark on his chest, which he said was from a tear gas canister shot directly at him. Others showed a Reuters reporter rubber bullets they said were fired by police. Ibrahim Mattar, an official of the moderate Shia opposition group Wefaq, said two protesters had serious head wounds while dozens were taken away after inhaling tear gas. Bahrain, home to the US Navy's Fifth Fleet, has been gripped by its worst unrest since the 1990s after protesters took to the streets last month, inspired by uprisings that toppled the leaders of Egypt and Tunisia. The tiny kingdom has seen weeks of rallies by its Shia majority, which says it is discriminated against by the Sunni royal family. The unrest is being closely watched in Saudi Arabia, where Shias are some 15 percent of the population. Saudi, the world's top oil exporter has seen small protests in the Eastern Province, where its oil industry is based and which is home to most Shias in the conservative Sunni kingdom. In a statement earlier in the day, the Interior Ministry urged all protesters to return to the Pearl roundabout for their own safety. It said the police had cleared protest tents from Bahrain Financial Harbour after one policeman was stabbed and another was taken to hospital with head wounds. A Western banker who declined to give his name said the protesters had stopped him from entering the Financial Harbour: "They didn't let me through and they were very aggressive. This is not peaceful any more. It's time for police to stop this." SECTARIAN CLASHES There have been few major confrontations between protesters and police since last month, but clashes have erupted between mainly Shia opponents of the government and Sunni supporters. In Hidd, near Bahrain's airport, a Reuters witness saw groups of Sunni residents checking the identities of those entering the area. At some entrances, vigilantes wore orange vests to identify each other. In another incident, police fired tear gas to separate a group of Shia Muslim protesters at Bahrain University from a group of Sunnis armed with sticks, witnesses said. Wefaq said it would hold the interior minister responsible for any attack on protesters by armed civilians. Sectarian clashes have also broken out in schools and streets in recent days, and rumors spread that shops owned by Shia businessmen were attacked or closed in Sunni areas. "These actions are intended to spread sectarian tensions," the Chamber of Commerce and Industry said in a statement. "This sensitive situation that the kingdom is passing through cannot stand any more tension and escalation as the biggest loser from this...is the national economy that has been exposed to major losses in the recent period." Thousands of Bahraini youths still occupy Pearl roundabout. But the opposition appears increasingly split, between the mainstream, which wants peaceful rallies calling for a new government and constitutional reform, and smaller groups intent on bringing down the royal family with more provocative action. "It was a mistake to go to the Financial Harbour. There is enough room in the square for protests," said a moderate opposition activist who did not give his name. "It was a small group and it's not popular, the consensus was on the square."