US warns of "imminent attack in Kenya"

06/24/12: Al Jazeera reports the US embassy in Kenya has warned of an imminent threat of an attack on the Kenyan port city of Mombasa and asked all its government workers to leave the coastal town, which has been hit by a series of attacks in the past.  Underscoring the threat, police said they recovered suspected bomb-making material in the capital Nairobi on Saturday, the second such discovery this week in the country.  Mombasa, the capital Nairobi and other parts of Kenya have suffered a series of grenade attacks since Kenya sent troops into Somalia last year to pursue al-Qaeda-allied al-Shabab fighters it blames for a surge in violence and kidnappings threatening tourism in east Africa's biggest economy.  The embassy also advised private citizens to heed the warning while planning their travels.