Somali pirates fired grenades and automatic weapons at an American freighter loaded with food aid but the ship managed to escape the attack and was heading Wednesday to Kenya under US Navy escort, officials said. Despite President Barack Obama's vow to halt their banditry, and the deaths of five pirates in recent French and US hostage rescue missions, brigands seized four vessels and over 75 hostages off the Horn of Africa since Sunday's dramatic rescue of an American freighter captain. “Our latest hijackings are meant to show that no one can deter us from protecting our waters from the enemy because we believe in dying for our land,” one pirate, Omar Dahir Idle, said by telephone from the Somali port of Harardhere. • A French warship patrolling waters off East Africa as part of an EU anti-piracy force intercepted a pirate “mother ship” on Wednesday and arrested 11 gunmen, the French defence ministry said.