In the first attack on a Western target in Kenya since the Islamist terrorist siege of Nairobi’s Westgate mall left 67 dead, a hand grenade was thrown Thursday at a bus carrying British tourists in the Kenyan capital, without exploding. Kenyan police also reported that four of Westgate attackers had escaped. In New York, NYPD commander Raymond Kelly warned against the staging of attacks like Westgate on a “soft target” in his and other American cities.