Mogadishu - Officials in Somalia say two people have been arrested in connection with Saturday's massive truck bombing that killed more than 300.A Somali intelligence official investigating the attack tells The Associated Press that a well-known man who vouched for the truck and persuaded soldiers to allow it into Mogadishu is now in jail. The official spoke on condition of anonymity because he was not authorized to speak to reporters.The official says the truck bomber had an accomplice driving a minivan packed with explosives that took another route but was stopped at a checkpoint near Mogadishu's airport.A senior Somali police officer, Capt. Mohamed Hussein, says that driver is now being held in a local prison.14:15 A senior Somali police official says at least three people, including a pregnant woman, are injured after security forces opened fire while trying to disperse protesters marching toward the site of Saturday's huge truck bombing in Mogadishu.Captain Mohammed Hussein says both Somali police and African Union soldiers were at the scene and opened fire.Thousands of people are marching through Mogadishu in a show of unity and defiance after the bombing killed more than 300 people and wounded nearly 400. Scores remain missing.13:00Pope Francis has deplored the Somalia bombing that killed more than 300 people and wounded nearly 400 others.At the end of his Wednesday public audience in St Peter's Square, Francis said "this terrorist act merits the strongest laments" especially since it struck an already suffering population.He prayed for the dead and wounded in Saturday's truck bombing in Mogadishu. Francis also appealed for the "conversion of the violent ones" and encouraged work for peace.12:45 Somali police say African Union soldiers have fired at angry protesters marching toward the site of the country's deadliest attack.Officer Ahmed Ali says the troops were responding after some protesters threw stones at them.Thousands of people are marching through Mogadishu in a show of unity and defiance after Saturday's truck bombing killed more than 300 people and wounded nearly 400. Scores remain missing.Somalia's government has blamed the attack on the al-Shabab extremist group, which often targets Mogadishu but has not commented.12:30Thousands of people have taken to the streets of Somalia's capital in a show of defiance after the country's deadliest attack.Wearing red headbands, the crowd of mostly young men and women is marching through Mogadishu amid tight security."May Allah punish those who massacred our people," said university student Mohamed Salad.The crowd marched toward the site of Saturday's truck bombing, which killed more than 300 people and wounded nearly 400. Scores remain missing."You can kill us, but not our spirit and desire for peace," said high school teacher Zainab Muse.Somalia's government has blamed the attack on the al-Shabab extremist group, which often targets Mogadishu but has not commented.Mayor Thabit Abdi called for Wednesday's march, saying "we must liberate this city which is awash with graves."