Israeli forces have bombed parts of central Gaza, killing at least eight Palestinians in the Al-Nuseirat camp area, while fighting with Hamas militants raged in Rafah city in the south, where health officials say another five residents were killed.
Into the 10th month of war, Israel's aerial and tank shelling of central Gaza has intensified in the past week, killing dozens.
Residents said the Israeli army blew up dozens of homes there in the past three days.
Palestinian health officials said eight people were killed in two separate Israeli air strikes on two houses earlier on Friday in Al-Nuseirat.
In Rafah, where Israel said it aimed to dismantle the last battalions of Hamas' armed wing, residents said fierce gun battles were heard on Friday in central and western areas.
Medics said five people died in Israeli fire and their bodies were moved to Nasser Hospital in nearby Khan Younis city.
The Al-Mawasi area, a humanitarian-designated zone where the Israeli army had been urging displaced Palestinians to go, has become unsafe, residents said, due to deadly Israeli attacks.
"They told us al-Mawasi was safe - we came to the safe place - what safety? There is no place in Gaza that is safe. They are the ones who told us to go to al-Mawasi in Khan Younis," said a widowed Palestinian woman, Aziza Suleiman Ammar.
"We came according to what they said, and they hit us also in the camp - go and see inside the tents, it's all shrapnel.
"There's nowhere for us. The house is gone. I have no house, my house is gone. My husband is gone, God knows what's next."
Mawasi on the western outskirts of Khan Younis has been sheltering hundreds of thousands of Palestinians who fled to the area after Israel declared it a safe zone.
Israel said attacks were "intelligence-based" and targeted militant leaders after steps were taken to ensure no harm to civilians - a claim Palestinians reject as false.
On Thursday, Prime Minister Benjamin Netanyahu, who is due to address the US Congress next week, made a surprise visit to Israeli troops in the area around Rafah, telling them that military pressure combined with a demand to bring back 120 hostages still held in Gaza was producing results.
"This double pressure is not delaying the (ceasefire) deal, it is advancing it," he said, according to a statement from his office.
A ceasefire effort led by Qatar and Egypt and backed by the United States has failed due to disputes between the warring sides, who blame each other for the impasse.
Israel vowed to eradicate Hamas after its fighters killed 1200 people and took more than 250 hostage in an October 7 attack, according to Israeli tallies.
At least 38,848 Palestinians have been killed in Israel's retaliatory offensive since then, Gaza health authorities say.
On Tuesday, Israel said it had eliminated half of the leadership of Hamas' military wing and killed or captured about 14,000 fighters since the start of the war.
Israel says 326 of its soldiers have been killed in Gaza.
Hamas does not release figures of casualties among its ranks and said Israel exaggerates to portray a "fake victory".