Hamas terrorists have 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 12 Palestinians, including a pregnant woman and her 14-month-old niece, have also been killed.
Israeli forces hit dozens of targets throughout Gaza in countersrikes, including terror sites concealed in homes or residential areas.
The army also moved armoured units towards Gaza as the sides headed closer to all-out war.
In Sunday’s fighting, Moshe Agadi, a 58-year-old Israeli father of four, was struck in the chest by shrapnel in a residential courtyard.
The Barzilai Medical Centre said a 49-year-old man was killed when a rocket hit an Ashkelon factory, while a second man was killed when his vehicle was hit by a projectile near Yad Mordechai, a small border community.
Israeli medical officials said a Thai labourer was critically wounded in a rocket strike.
The Israeli military said terrorists had fired more than 600 rockets into Israel, and that Israeli forces had launched some 260 air strikes against militant targets in Gaza.
Palestinian health officials reported 12 dead, including eight terrorists.
The other dead included a pregnant woman and her niece, who were killed in what the officials said was an Israeli air strike. The Israeli military denied involvement, saying the woman and baby were killed by a misfired Palestinian rocket.
Palestinian officials identified one of the dead as Hamas commander Hamed al-Khoudary, who Israel said was a key player in transferring Iranian money to the group.
The sudden outburst has broken a month-long lull as Egyptian mediators had been trying to negotiate a long-term ceasefire.
Israeli military spokesman Lt Col Jonathan Conricus said Israel’s strikes hit a variety of “high-quality” sites, including commanders’ homes in which terror activity was observed.
The military spokesman said Israel was deploying an armoured brigade along the Gaza front, with tanks ready for offensive missions as needed.
The Israeli military has already struck rocket launchers, tunnel shafts, training sites, storage depots and warehouses of both the territory’s Hamas rulers and the smaller, Iranian-backed Islamic Jihad group.
Israeli Prime Minister Benjamin Netanyahu said Hamas was paying a “heavy price” for its rocket attacks, as well as those by Islamic Jihad.
Sirens wailed along the border region overnight and throughout the day warning of incoming attacks.
School was cancelled and roads were closed.
In Gaza, large explosions thundered across the blockaded enclave during the night as plumes of smoke rose into the air.
One of the air strikes hit a six-storey commercial and residential building that housed the office of Turkey’s official Anadolu news agency.
“We thought the Rimal neighbourhood is safe, but it seems there is no safe place in Gaza,” said Nidal al-Dali, who lived in the building and lost his home.
Turkish foreign minister Mevlut Cavusoglu called it a “new example of Israel’s unrestrained aggression”.
The Israeli military said its Iron Dome defence system intercepted more than 150 of the projectiles from Gaza, but several still managed to slip through.
A rocket scored a direct hit on a residential home in the border town of Sderot.
Dr Ron Lobel, deputy director of the Barzilai Medical Centre in Ashkelon, said teams had treated more than 110 people, most from shock symptoms, but several with physical wounds.
In a first, the hospital itself was also hit by debris from a rocket that was intercepted by an Iron Dome missile.
There were no injuries, but the debris struck the hospital’s oncology unit, bursting a pipe and sending water pouring from a ceiling into the hallway.
Israel has vowed to hit back hard against both Hamas and Islamic Jihad, whom it suspects of triggering the current conflagration.