- A statement said some of the suspects had been hiding among the civilian population and surrendered voluntarily.
- At least 20,000 people have been killed and 50,000 injured in Gaza since then, according to the Hamas-run health ministry.
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 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.
At least 20,000 people have been killed and 50,000 injured in Gaza since then, according to the Hamas-run health ministry.
Israel has kept up its bombing campaign in Gaza - ordering civilians to flee.
The UN said the latest order affected 150,000 people in the middle of the Strip.
"People in Gaza are people," wrote 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. A medic named Ziad told Reuters news agency he was left asking where to go, as there was "no safe place".
Palestinian news agency Wafa reported on Saturday that Bureij had been shelled. Additional strikes on the Jabalia and Nuseirat camps had left "dozens" dead, it said.
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.
Saturday's joint statement by the Israel Defense Forces (IDF) and internal security service Shin Bet said the questioning of 200 fighters 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.
Meanwhile, the president of the UN Security Council has said a resolution adopted on Friday represents a crucial step towards averting a humanitarian catastrophe in Gaza.
On Friday, the council adopted a resolution that aimed to introduce "extended humanitarian pauses and corridors" throughout Gaza.
The vote followed days of negotiations to avoid a veto by Israel's key ally, the US.
But the motion fell short of calling for an immediate ceasefire in the war.
The US and Russia abstained on the vote, while the 13 other members of the council - including the UK, which had previously abstained on a similar resolution - backed the text, which called for creating conditions "for a sustainable cessation of hostilities".
The resolution also demanded that parties "allow, facilitate and enable the immediate, safe and unhindered delivery of humanitarian assistance at scale directly to the Palestinian population throughout the Gaza Strip".
Hamas criticised what it said was an "insufficient step" to meet the humanitarian needs of people in Gaza, and accused the US of working hard to "empty this resolution of its essence".
The resolution also called for "the immediate and unconditional release of all hostages". The Israeli military urged the international community and international organisations to enforce it.
UN Secretary General António Guterres said Israel's offensive was creating "massive obstacles" to the distribution of aid in Gaza.