has been taking a very, very ugly turn, the deadliest day yet. more than a dozen israeli soldiers, nearly 90 palestinians killed on sunday alone. two of the casualties on the israeli side are americans. and secretary of state john kerry left washington about five hours ago. he s on route to the region. first stop cairo. he hopes to try to broker a ceasefire. he ll eventually show up here in israel. other stops as well. but first, let s go to gaza to cnn s karl penhaul who is on the scene for us. carl, what are the latest developments right now? reporter: wolf, there is still heavy fighting apparently going on in eastern parts of gaza. we ve heard air strikes going in. we ve heard artillery occasionally, also. we ve heard the sound of assault rifles firing, possibly an indication that there s some kind of hand-to-hand fighting going on between israeli troops and militant factions there.