CAIRO - A roadside bomb killed three Egyptian soldiers in the Sinai peninsula on Monday, security sources said.The blast, which also wounded a soldier, comes days ahead of an investment conference in Sharm el-Sheikh resort, which Egypt hopes will project an image of stability and secure billions of dollars.The bomb targeted a military vehicle in Sinai, home to Egypt's most dangerous Islamist militant group, Sinai Province.Formerly known as Ansar Bayt al-Maqdis, it has pledged allegiance to Islamic State, the ultra-hardline Sunni group which controls large parts of Iraq and Syria.Sinai-based militants have killed hundreds of soldiers and police since the army toppled Islamist president Mohamed Morsi in 2013.