ASHKELON — Saif Abu Keshek, identified by Israel's foreign ministry as a leading member of the Popular Conference for Palestinians Abroad, appeared in an Israeli court in Ashkelon on Sunday following his detention from a Gaza-bound aid flotilla. Fellow activist Thiago Ávila also appeared in court, and the state asked to extend the detention of both men by four days.

Israeli forces intercepted the flotilla of more than 50 vessels in international waters off Greece early on Thursday. Organisers of the flotilla said the interception took place more than 620 miles (1,000 km) from Gaza. The vessels had set sail from France, Spain and Italy to break an Israeli blockade of Gaza and bring supplies to the Palestinian territory.

Israeli forces removed 175 activists from the flotilla. Dozens of the intercepted activists disembarked on the Greek island of Crete on Friday, while two activists were taken to Israel for questioning.

Israel's foreign ministry said the two activists were affiliated with an organisation subject to U.S. Treasury sanctions. The Popular Conference for Palestinians Abroad has been accused by the U.S. Treasury of clandestinely acting on behalf of Hamas. The ministry said Ávila was linked to the same group and suspected of illegal activity.

Spain condemned the detention of Abu Keshek and rejected the Israeli accusation against him. Lawyers from the legal rights group Adalah met the two detained activists at Shikma prison in Ashkelon on Saturday.

According to Adalah, Abu Keshek was hand-tied and blindfolded and forced to lie face-down on the floor from the moment of his seizure until reaching Israel. Adalah said Ávila had been kept in isolation and blindfolded since arriving in Israel.

Adalah relayed an account from Ávila describing his treatment during the operation. "I was dragged face-down across the floor and beaten so severely that I passed out twice," Ávila said.

Three released activists have pledged to go on hunger strike until the health and whereabouts of the two detained flotilla leaders is confirmed.