About a hundred pro-Palestinian activists were being prevented by Swiss police early Sunday from boarding a flight at Geneva airport bound for Tel Aviv, the "Welcome to Palestine" campaign said.
"The information we have obtained from activists is that there is a high presence of police there and the police are trying to prevent them from boarding," said campaign spokesman Anas Muhammed in a telephone call to AFP.
"Besides that there has been the confiscation of a passport of one of the activists."
The Swiss and French activists had bought their tickets in advance and were due to fly on a 6:30 am (0430 GMT) flight to Tel Aviv, Muhammed said.
"They are going to visit Palestinians who are under occupation, they are going to visit the West Bank."
Israeli security forces last week began bracing for a "fly-in" of hundreds of pro-Palestinian activists expected to arrive at Ben Gurion airport outside Tel Aviv this weekend.
The activists, mainly from European countries, are expected to openly declare their intention to visit the Palestinian West Bank, but Israel vowed to prevent them even from arriving.
French carrier Air France and British low fares airline Jet2.com have joined Germany's Lufthansa in cancelling seats on flights to Tel Aviv after Israel raised objections.
The "Welcome to Palestine" campaign is taking place for a third consecutive year.
The campaign's organisers in the West Bank say they want to publicise Israel's control of movement into and out of the Palestinian territory and to boost solidarity with the Palestinian people.
The admin of the "Air Flotilla 2" account on twitter accused a list of airlines who adopted the exact Swiss preventive measure of supporting "Israeli apartheid" against the Palestinians by cancelling the tickets of the participants.
"The goal of Air Flotilla 2 was to show that West Bank is one big prison for the Palestinians; Israel proved it before the first plane took off," activists on the account said on Sunday.