Kenyan police said on Friday they shot and killed two armed men suspected of planning an attack on a ferry in the port city of Mombasa after one of them tried to hurl a grenade at approaching police. Mombasa and the coastal region has been struck by a series of attacks that have killed dozens of people in recent months. The worst shootings have been on the north coast, but Mombasa has been hit by several bomb attacks. Somalia's al Shabaab Islamist group has claimed many attacks, but the government has blamed some of the north coast raids on local political networks, leaving many Kenyans confused about who is responsible and angry at security failures.