At least 19 people have been killed and 60 others injured in an Israeli airstrike in a humanitarian zone in the Gaza Strip, according to Palestinian officials. The militant Palestinian organization Hamas had initially spoken of at least 40 dead. Later, the Health Ministry reported 19 deaths, although other Hamas authorities continued to speak of 40 Palestinians killed. The Israeli army said the attack was aimed at key Hamas terrorists in a command centre hidden in the zone. It also denied the high death toll. Footage from the site showed a huge crater in the ground and people desperately diggi…