Israel says it has arrested 200 members of the Hamas and Islamic Jihad groups in the past week and taken them into its territory for questioning.
A statement said some of the suspects had been hiding among the civilian population and surrendered voluntarily.
Israel says 700 Palestinian militants have been arrested since it launched its military operation and invasion of Gaza with the aim of eliminating Hamas.
Hamas says mostly women and children are being killed by the Israelis.
The BBC is unable to verify the claims. Israel has previously stressed that it takes steps to avoid civilian casualties, and blames Hamas for embedding itself in densely-populated areas.
Israel launched its retaliatory operation after Hamas fighters crossed from Gaza into southern Israel on 7 October, killing 1,200 people and taking about 240 hostages.
More than 20,000 people have been killed and 53,000 injured in Gaza since then, according to the Hamas-run health ministry.
Its update on Saturday said another 201 people had been killed and 368 others injured in the previous day alone.
The UN earlier announced that its aid worker Issam al-Mughrabi, 56, had been killed in a strike – along with his wife, children and more than 70 members of his extended family.
Israel announced that five more of its soldiers had been killed in fighting in Gaza, bringing the total to 144 to since it launched its ground operation.
The military has kept up its bombing campaign in Gaza – ordering civilians to flee.
On Saturday, it said one of its fighter jets had killed Hassah Atrash, a man it accused of smuggling weapons into Gaza to arm Hamas. There was no confirmation from Hamas.
The Israeli military has said it has almost full operational control of the north of the Gaza Strip, and is stepping up operations in the south.
The UN said the latest evacuation order affected 150,000 people in the middle of the territory.
“People in Gaza are people,” commented Thomas White from UNWRA, the agency for Palestinian refugees. “They are not pieces on a checkerboard – many have already been displaced several times.”
The latest evacuation order impacted people in the Bureij refugee camp, who were told to head towards Deir al-Balah city further south.
Palestinian news agency Wafa reported on Saturday that Bureij had been shelled – as had the Jabalia and Nuseirat camps, among other locations.
A medic named Ziad told Reuters news agency he was left asking where to go, as there was “no safe place”.
An adviser to the Israeli prime minister has acknowledged “terrible suffering” in Gaza – but told the BBC this was because the territory’s Hamas leadership “don’t give a hoot” for the people there.
The suffering “shouldn’t have happened” but came about after a “declaration of war” by Hamas on 7 October, said Mark Regev.
The questioning of 200 new suspects was announced in a joint statement on Saturday by the Israeli military and internal security service Shin Bet.
The statement said this followed the arrests in Gaza of “hundreds of suspects involved in terrorist activities”.
The BBC is not able to independently verify all battlefield claims. However, it did verify video earlier this month showing the detention of dozens of Palestinian men in the north Gaza Strip.