Gaza militants on Sunday intensified a wave of rocket fire into southern Israel, striking towns and cities and killing at least three people in one of the bloodiest rounds of fighting since the 2014 war. At least nine Palestinians, including a pregnant woman and her 14-month-old niece, have also been killed.

A cellphone video went viral Sunday after a rocket landed next to a bus full of Israel soldiers - illustrating the many close-calls in the south of the country, which is under heavy rocket fire.

A similar video went viral on Saturday, as footage of a family reacting in horror to a rocket explosion directly in front of their car in Ashkelon was posted to social media.

Israeli forces struck dozens of targets throughout Gaza, including militant sites that the military said were concealed in homes or residential areas. The army also moved armored units toward Gaza as the sides headed closer to all-out war.

Israel and Hamas are bitter enemies that have fought three wars since the Islamic militant group seized control of Gaza in 2007, as well as numerous smaller flare-ups, most recently in late March.

These flare-ups have become increasingly frequent in recent years, ending in informal Egyptian-mediated truces in which Israel pledges to ease a crippling blockade on Gaza imposed after the Hamas takeover while the militants promise to halt rocket fire.

As with previous rounds of fighting, the latest violence began late last week amid Palestinian accusations that Israel was not moving quickly enough to ease the blockade.

The Associated Press contributed to this story