Israel may be preparing for a ground battle with the Palestinian Islamist organization Hamas.
Hostilities between Israel and Hamas militants have been escalating since the killing of 3 Israeli teenagers.
The Israeli military is continuing its airstrikes on the Gaza Strip to destroy Hamas's rocket launch sites and weapons depots.
The Palestinian health ministry in Gaza says 79 people, including women and children, have been killed and more than 570 others wounded.
In response, Hamas fighters have been firing rockets from Gaza into Israel.
They fired 4 rockets at Jerusalem on Thursday evening. No one was injured thanks, in part, to the Israeli military intercepting some of the missiles.
Air raid sirens wailed near NHK's Jerusalem bureau. Our correspondent saw a rocket downed by an interceptor missile.
The rocket attacks have prompted the Israeli government to call up 23,000 reserve officers.
The government is also urging the evacuation of Gaza residents living near the border with Israel.
Jul. 10, 2014 - Updated 22:27 UTC