Israel’s ground forces expanded operations in Gaza on Friday night in the largest military advance since the war began.

Frequent heavy explosions lit up the coastal enclave in what witnesses said was the most intense bombardment of the war so far, while Hamas’s military wing said it was fighting Israeli forces on the ground.

The onslaught began shortly after Israel accused Hamas of using the Strip’s 1,500-bed Al-Shifa hospital as a shield for the group’s command structure.

Internet and phone services collapsed as the bombardment intensified, largely cutting off Gaza’s 2.3 million trapped residents from each other and from the outside world.

The latest escalation followed two overnight tank raids into the Strip which the Israel Defense Forces (IDF) said were missions to start to prepare the ground for an offensive.

The country’s war cabinet reportedly made the decision to expand operations after talks on a possible hostage release ended in a stalemate.

Rear Adm Daniel Hagari, Israeli military spokesman, said: “In the last hours, we intensified the attacks in Gaza. In addition to the attacks carried out in the last few days, ground forces are expanding their operations tonight.”

Israeli aircraft were conducting extensive strikes on tunnels and other targets, he said. There were reports last night from Palestinians within Gaza that Israeli tanks were exchanging fire with Hamas gunmen.

The military did not officially announce the start of a ground invasion, but the escalation appeared to signal the IDF may be moving closer towards a land offensive on Gaza, where it has pledged to wipe out the ruling Hamas group. As explosions rocked the territory, Hamas called on the world to “act immediately” to stop Israel pounding the territory.

“We call on the Arab and Muslim countries and the international community to take responsibility and act immediately to stop the crimes and series of massacres against our people,” the group said.