GAZA, Sept. 16 (Xinhua) -- The Israeli army intensified its airstrikes on Gaza City early Tuesday in what some residents and observers described as a possible prelude to expanding ground operations inside the city, amid rising casualties and a worsening humanitarian crisis among the Gaza population.

Palestinian sources told Xinhua that warplanes and drones continuously targeted multiple neighborhoods, supported by artillery and helicopter fire, while the Israeli army said it had carried out "a series of large-scale attacks" that would "gradually increase in intensity" in the coming days.

Israeli media reported that more than 35 sites were hit, including the neighborhoods of al-Sabra, al-Daraj, Sheikh Radwan, the al-Shati refugee camp and Tal al-Hawa, with explosions reportedly heard as far away as in Jerusalem and Tel Aviv.

Medical sources in Gaza confirmed that several Palestinians, including women, children, and the elderly, were killed in the latest strikes, while dozens more were injured.

"The bombardment was the most violent wave of bombing in months," Ibrahim Hajjaj, a Palestinian man from al-Jalaa neighbourhood, told Xinhua.

"I thought that none of us would survive as the Israeli army did not stop its strikes during the whole night," he said. "However, we are still alive, but not sure if we will survive once again."

According to the civil defense, three houses near the General Security Intersection north of Gaza City were hit, leaving multiple casualties.

"A large number of dead and missing people remain under the rubble of completely destroyed homes," Mahmoud Basal, spokesperson for Gaza's Civil Defense, told Xinhua, adding that rescue crews face severe challenges due to shortages of equipment and fuel.

Basal also confirmed that several people were killed in an airstrike on the al-Sabra neighborhood, while another strike hit a home in western Gaza, causing additional deaths and injuries.

Local residents said that the army used heavy bombs that caused widespread destruction, prompting many families to flee into the streets overnight to escape the shelling.

"We ran out in our pajamas with nothing but our children in our arms," Ahmed Zaqout, a 42-year-old man from al-Sabra, told Xinhua.

"The entire street was shaking as if there were an earthquake. I could only think of carrying my youngest daughter, who is seven, while my wife held our baby," he recalled.

Meanwhile, residents said the Israeli army was creating a "ring of fire" around the Safina area in northwestern Gaza City, while troops had maintained positions near al-Sheikh Radwan pond in the north for days, without launching a large-scale ground incursion into residential districts.

"The army had planted explosives and established new lines of fire, while artillery and drones continued to target areas east and west of al-Jalaa Street," Wael Abu Ali, a Palestinian man from the al-Jalaa neighbourhood, told Xinhua.

Intermittent shelling was also reported in al-Mukhabarat, al-Karama, and al-Maqousi neighbourhoods northwest of Gaza City.

"It feels like they are suffocating the city from all sides before storming in," said Abu Khaled, a 55-year-old taxi driver displaced from Sheikh Radwan. "I have already moved my family twice, but every area we go to is being bombed. Now we are sheltering with relatives, but even here the windows rattle with every explosion."

"Gaza is burning. The IDF (Israel Defense Forces) strikes with an iron fist at the terrorist infrastructure and IDF soldiers are fighting bravely to create the conditions for the release of the hostages and the defeat of Hamas," Israeli Defense Minister Israel Katz wrote on social media.

"We will not relent and we will not go back -- until the completion of the mission," he stressed.

Hamas said in a press statement that the Israeli army's ongoing bombardment of Gaza City, including "the shelling of residential neighborhoods, the destruction of towers, and the forced displacement of civilians," amounted to "ethnic cleansing and genocide."

"The enemy's reliance on massacres, starvation, and destruction will fail, as it has failed before," said Hamas, while holding Israeli Prime Minister Benjamin Netanyahu "responsible for the fate of the captured soldiers in Gaza."

Residents who survived the overnight strikes expressed fear of a looming ground offensive. "We know this level of bombing means they want to come in," said Umm Rami, a mother of four from al-Shati refugee camp. "But where can we go? The shelters are overcrowded, and the streets are full of families with nowhere to hide."

Another resident, 27-year-old university student Lina Hamad, said she had been preparing for her graduation exams when the bombing forced her family to leave their home in al-Daraj. "My books are still on the table, but the house is no longer safe," she said. "I don't know if I will ever go back to continue my studies."