The Israeli military has ordered Palestinians to leave a wide sweep of land to the east of the southern Gaza city of Khan Younis after rockets were fired towards Israel.
People in the area first received audio messages telling them to leave, before the Israeli military posted a message in Arabic repeating the warning to social media.
Witnesses say many people are already fleeing.
It comes after about 20 rockets were launched in the heaviest such attack in months, with a number intercepted and others landing in open areas with no injuries reported.
Palestinian Islamic Jihad (PIJ) said it launched the barrage in response to Israeli “crimes”.
The latest evacuation order covers the area around the European hospital to the south-east of Khan Younis.
Staff have begun moving some key equipment to Nasser hospital in Khan Younis and some staff and patients have also left, local reports say.
Elsewhere, fierce fighting continued for a fifth day in Shejaiya in the north of Gaza and an Israeli soldier was killed in the southern Rafah area.
On Sunday, Israel’s prime minister said its troops were engaged in a “difficult fight” across the entire Palestinian territory.
The Israeli military launched a campaign to destroy Hamas in response to an unprecedented attack on southern Israel on 7 October, during which about 1,200 people were killed and 251 others were taken hostage.
More than 37,900 people have been killed in Gaza since then, including 23 over the past 24 hours, according to the territory’s Hamas-run health ministry.
On Monday morning, sirens sounded in Israeli communities near the Gaza border fence, many of which have been evacuated since the 7 October attack.
The Eshkol Regional Council later reported that 18 rockets were launched towards areas it governs, according to the Jerusalem Post. Most landed in open areas, but one fell “in the area of Kibbutz Holit’s fence”, it said. Another rocket was intercepted by the Iron Dome missile defence system, it added.
The Times of Israel reported that Monday’s barrage was the largest from Gaza since January, when at least 25 rockets were launched towards the city of Netivot.
The Israel Defense Forces (IDF) said the latest rocket-fire had come from the southern Khan Younis area and that its artillery had struck the sources.
Palestinian news agency Wafa reported that artillery strikes on Monday killed one civilian and wounded several others in the town of Khuzaa, which is south-east of the city of Khan Younis.
Israeli warplanes had also targeted a street in Shejaiya, in the east of Gaza City, and an area north of Nuseirat refugee camp, in central Gaza, it said.
Hamas’s military wing meanwhile said its fighters had targeted two Israeli tanks with explosive devices in Shejaiya.
The IDF said in a statement that its troops had “eliminated numerous terrorists in close-quarters encounters and located large quantities of weapons” during raids in Shejaiya. Air strikes had killed about 20 others and destroyed weapons manufacturing and storage facilities in the area, it added.
A battle has raged there since Thursday, when Israeli troops went back into the area following what the IDF said was “intelligence indicating the presence of terrorists and terrorist infrastructure”.
Over the weekend, residents said the assault had left bodies lying in the street, while the IDF said two Israeli soldiers had been killed in combat in northern Gaza.
The UN agency for Palestinian refugees (Unrwa) said up to 80,000 people in Shejaiya and surrounding areas had been told by the IDF to evacuate and head south, but that they were being pushed westwards because they could not pass through Israeli checkpoints in the Wadi Gaza area.
“The Israeli army has completely destroyed the neighbourhood,” a woman from the neighbouring Tuffah district told BBC Arabic’s Gaza Lifeline programme.
“Along with others, I fled as shells rained down around us. We moved from one area to another until we managed to escape the neighbourhood. But many residents were trapped and unable to leave,” she added.