Lufthansa airline has cancelled the tickets of several pro-Palestinian activists who were supposed to fly to Tel Aviv on Sunday.
"Dozens of passengers who bought a plane ticket to travel to Tel Aviv Sunday on April 15 were notified Thursday by the airline Lufthansa that their reservation was cancelled, 'by order of Israel'," reads a statement on the group's website.
Employees of the German airline told passengers that "Israel has produced a list of names of persons to whom this country denies entry".
Israeli security officials reportedly tracked the activists on social media sites such as Twitter and Facebook and compiled a blacklist of more than 300 names. Then, they asked airlines to keep those on the list off flights to Israel.
The company defended itself saying that it is obliged "by the principle of following the laws and guidelines on entry to the territory of countries to which it transports its passengers".
The organisers, however, denounced Lufthansa's move as a violation of international law and said that passengers "will arrive, as expected, at airports this weekend".
The activists were expected to arrive at Ben Gurion airport in Tel Aviv as part of the 'flytilla' - a solidarity campaign called "Welcome to Palestine" - but Israel has vowed to prevent them from entering the country.
Nitsana Darshan-Leitner of the Israel Law Centre, said she had asked Attorney General Yehuda Weinstein "to put an end" to the campaign, now in its third year.
"We are asking him to put them on trial," she told Israeli public radio.
"This is criminal activity... (which is) a breach of several laws in Israel including unauthorised assembly and crossing the border when they have been specifically told not to come here."
Minister of public security Yitzhak Aharonovitch said Tuesday the "provocateurs will be dealt with in a determined and quick way."
"If they arrive to Israel they will be identified, removed from the plane, their entry into Israel will be prevented and they will be moved to a detention facility until they are flown out of Israel," Aharonovitch said.
Around 100 activists managed to get in and travel to the West Bank, access to which is controlled by Israel, during the first "Welcome to Palestine" campaign in 2010.
Last year, however, Israel worked with airlines to prevent hundreds of activists from flying to Ben Gurion airport and detained and later deported others who managed to arrive.