US President Barack Obama arrived in his ancestral homeland Kenya late Friday, with a massive security operation under way to protect him from Al-Qaeda-linked Somali militants. Obama, making his first visit as president to his father's birthplace, adressed an entrepreneurship summit on thursday before holding bilateral taks with President Kenyatta at the State House. The Us president will also hold talks on trade and investment, security and counter-terrorism, and democracy and human rights. Parts of the Kenyan capital Nairobi have been locked down and airspace will be closed during the president's arrival late Friday and his departure late Sunday, when he travels up the Rift Valley to neighbouring Ethiopia, the seat of the African Union. Obama is celebrated as a hero throughout the country, yet many Kenyans have been disappointed it has taken him until almost the end of his second term in office to make the trip.