Israel's Supreme Court on Wednesday upheld a decision to bar entry to the Jewish state to a Polish humanitarian worker for having unspecified links to "terrorist elements".
Although Kamil Qandil had a valid visa when he landed at Ben Gurion airport near Tel Aviv on September 2, he was refused entry by immigration officials and held at the airport as he filed an appeal.
Upholding the ban, Chief Justice Asher Grunis cited "new material which points to the appellant having contacts with terrorist elements, which was not known at the time when he was granted the visa," without elaborating.
"I have done nothing which could have harmed the state of Israel," Qandil, who has a Palestinian father and Polish mother, told the court during the hearing.
Part of the hearing was held in the presence only of the judges and agents of Shin Bet, Israel's internal security service.
"The hearing today and the court's verdict did little to clear the mystery about the allegations against Kamil," his lawyer, Yadin Elam, told reporters.
"He still does not know what he is accused of and when he addressed the court and explained it to the judges, Chief Justice Grunis replied that maybe Kamil is unaware of it," Elam said.
The Association of International Development Agencies (AIDA), which groups more than 80 organisations, said on Tuesday Qandil was employed by Polish Humanitarian Action (PAH) on a project to supply water to Palestinians in an area of the southern West Bank under full Israeli control.
"He said that the biggest losers would be the villagers of the south Hebron hills where the project is located and... the Polish taxpayers who fund it," a relative told AFP after the verdict.
AIDA said PAH was seeking to refurbish rainwater cisterns on which Palestinian farmers depend for irrigation. Israel has demolished several refurbished cisterns, triggering a diplomatic response from Warsaw.
Contacted by AFP in Warsaw on Wednesday, PAH declined "any immediate comment".
Shin Bet told Haaretz newspaper on Monday that Qandil was refused entry "due to security information that exists about him."