MOGADISHU (Reuters/AFP) - A suicide car bomber killed six policemen and a civilian on Sunday in Somalias capital Mogadishu, where insurgents are fighting pro-government forces. Abdifatah Shaweye, Deputy Governor of Mogadishu, said the bomber drove a pickup truck to the gate of a police headquarters and detonated it in front of the guards. Four died on the spot, two others died of serious injuries, and one civilian (died), a police commander, who asked not to be named, told Reuters. At least 53 people have died since Friday morning, when the government attacked rival groups strongholds in the city. Neighbouring states and Western governments fear Somalia, which has been mired in civil war for 18 years, could become a haven for people linked to Al-Qaeda unless the new government under President Sheikh Sharif Ahmed can defeat them. Al-Shabaab group, which Washington says has links to Al-Qaeda, has been spearheading the rebel offensive with allied guerrilla group Hizbul Islam. They stepped up attacks in the capital early in May. Saturdays edition of The Times in London reported that security officials had seen more than 290 fighters from Britain, the United States, Canada, Pakistan, Afghanistan and Saudi Arabia enter Mogadishu in recent weeks. Security sources say the insurgents have been planting more sophisticated roadside bombs in recent months and suicide attacks have become more frequent. Two suicide bombers - one wearing an explosive vest and another in a car - infiltrated a compound housing peacekeeping troops from Burundi in February and killed 11 soldiers in the worst single attack on the African Union force. On Sunday morning, more Mogadishu residents took advantage of a lull in the fighting to grab some belongings and flee to sprawling refugee camps outside the crumbling city. Meanwhile, fierce battles between government forces and rebels forced some 8,000 people to flee the Somali capital in one day, the United Nations said Sunday. Unfortunately, due to heavy fighting on Friday 22nd, the number of displaced from Mogadishu sharply increased, the office of the UN High Commissioner for Refugees said. An estimated 8,000 were displaced on Friday only, bringing the total number to 57,000, the UNHCR said in a statement. President Sharif Sheikh Ahmed is holed up in his compound with a handful of supporters and under African Union peacekeepers protection, while his forces have sought to drive out rebels from their strongholds in the city. The Somali capital has been ravaged by 18 years of almost uninterrupted civil conflict and emptied of hundreds of thousands of residents by the violent fighting that followed Ethiopias 2006 invasion.