A drill involving more than 1,000 people was held this morning in Tel Aviv. The drill simulated the fall of three missiles - one biological, one chemical and one conventional - on the city. When the siren sounded, students at three local schools filed into their school bomb shelters, evacuation centers were readied, and water was "distributed" to citizens. The drill is an annual event carried out by the Tel Aviv municipality, and is said to be unrelated to events in the Persian Gulf.