"They were questioned and didn't pass the questioning," police spokeswoman Luba Samri told AFP. "They are being detained at the moment and will probably be sent back where they came from."
Organisers of the "Welcome to Palestine" campaign, which some have called the "flytilla," had said up to 800 activists were to fly in to Ben Gurion Airport, near Tel Aviv, in a peaceful mission to visit Palestinian families.
But the Israeli authorities said they largely managed to preempt the campaign by foreign activists -- most of them from France -- demonstrating for the right of access to the West Bank.
Officials said that by notifying foreign airlines of ticket-holders who would not be admitted to Israel they prevented hundreds from boarding at their port of departure.