Turkey on Tuesday announced the detention of 33 people suspected of planning abductions and spying on behalf of Israel's Mossad intelligence service.
Interior Minister Ali Yerlikaya said the suspects were rounded up in raids across eight provinces in and around Istanbul.
It was not immediately clear if they were Israeli nationals or locals allegedly working with Mossad.
"We will never allow espionage activities to be conducted against the national unity and solidarity of our country," Yerlikaya said on social media.
Yerlikaya's office released video footage showing armed security service agents breaking down doors and handcuffing suspects in their homes.
The Istanbul public prosecutor's office said 13 additional suspects remained at large.
Relations between Turkey and Israel imploded following the outbreak of the Israel-Hamas war nearly three months ago.
Turkish President Recep Tayyip Erdogan has turned into one of the world's harshest critics of Israeli Prime Minister Benjamin Netanyahu.
The Turkish leader last week compared Netanyahu to Adolf Hitler and demanded that Israel's Western allies drop their support for the "terrorism" being conducted by Israeli troops.
Erdogan has also recalled Ankara's envoy to Tel Aviv and pushed for the trial of Israeli commanders and political leaders at the International Criminal Court in The Hague.
The president's ruling Islamic conservative party AKP also led tens of thousands of protesters out on the streets of Istanbul on Monday for one of Turkey's biggest anti-Israel rallies of the entire war.
The Gaza war ended a gradual thawing in Turkish-Israeli relations that culminated with the reappointment of ambassadors in 2022.
Israel and Turkey resumed long-stalled talks about a major Mediterranean Sea natural gas pipeline project that could have reshaped geopolitical alliances across parts of the Middle East.
Turkey won words of gratitude from Israel in 2022 for detaining a group of Turkish and Iranian nationals were allegedly planning to murder and kidnap Israeli tourists in Istanbul.
Erdogan and Netanyahu met briefly on the sidelines of a UN meeting in New York in September and were discussing holding a formal summit this year.
The Turkish MIT intelligence service conducts periodic raids against suspected Israel operatives working in major cities such as Ankara and Istanbul.
Most are accused of conducting surveillance work on Palestinians living in Turkey.
Istanbul served as one of Hamas's foreign political offices until the outbreak of the Gaza war.
Turkey informally asked Hamas leaders to leave days after militants conducted unprecedented raids into southern Israel that resulted in the deaths of around 1,140 people -- most of them civilians -- according to an AFP tally based on official figures.
The Islamists also took around 250 people hostage. Israeli officials believe more than half of them remain in Gaza.
The Gaza health ministry says Israel's hugely destructive military campaign aimed at destroying Hamas has killed around 22,000 people -- mostly women and children.
