The Shin Bet agency said in a statement that it had found an explosive device fitted with a camera and a mechanism that would allow it to be activated by Hezbollah from Lebanon.
It said the attack was to be carried out in the coming days.
The Shin Bet did not provide evidence linking the device to Hezbollah, which has been trading fire with Israel along the Lebanese border since the outbreak of the war in Gaza.
It did not say where the device was found or identify the target of the attack but said the official had been notified.
It said the device was similar to one found in a park in Tel Aviv in September 2023 that it said was intended to target a senior Israeli official.
The device last year went off without causing any injuries.
The Shin Bet said Hezbollah was behind both planned attacks.
In recent days Israeli officials have warned of a wider military operation to halt Hezbollah rocket attacks and allow tens of thousands of Israelis to return to their homes in the north.
The Security Cabinet has updated the objectives of the war to include the following: Returning the residents of the north securely to their homes.— Prime Minister of Israel (@IsraeliPM) Israel will continue to act to implement this objective.September 17, 2024
Hezbollah on Tuesday promised to retaliate after blaming Israel for detonating pagers that killed at least eight people and wounded 2750 others, including many of the militant group's fighters and Iran's envoy in Beirut.
Lebanese Information Minister Ziad Makary condemned the detonation of the pagers - used by Hezbollah and others in Lebanon to communicate - as an "Israeli aggression".
Hezbollah said Israel would receive "its fair punishment" for the blasts.
Returning residents who fled Israel's north due to cross-border fighting with Hezbollah is now an official war goal, Prime Minister Benjamin Netanyahu said on Tuesday.
Israeli officials have long said they aim to return the tens of thousands of displaced Israelis to their homes, so it was not immediately clear how the announcement would affect the conduct of the war.
Palestinian officials said on Tuesday Israel had struck a number of homes in the central Gaza Strip, killing at least four people including a child.
The Civil Defence first responders said more people were trapped under the rubble and the toll was likely to rise after the strikes early in the day.
Another strike late on Monday in Gaza City killed a man, his wife and child, according to the Civil Defence.
Israel says it only targets militants and tries to avoid harming civilians.
It accuses Hamas and other armed groups of endangering civilians by operating in densely populated areas.
The Civil Defence said that their rescue crews came under Israeli fire as they arrived in the area, injuring one.
The Israeli military said it was targeting militants preparing to fire at troops and was reviewing "reports regarding harm to uninvolved civilians".
Gaza's Health Ministry says more than 41,000 Palestinians have been killed since the start of the war, which was ignited by Hamas' October 7 attack into Israel.
It does not differentiate between civilians and combatants but says more than half of those killed were women and children.
The Israeli military says it has killed more than 17,000 militants.
Hamas-led militants killed 1200 people in the October 7 attacks and took another 250 hostage.
They are still holding about 100 captives, a third of whom are believed to be dead, after most of the rest were released during a ceasefire in November.
with Reuters
