(CNN) -- Four Israeli Arabs on the Gaza aid flotilla remained in Israeli custody Wednesday, according to Israeli sources and the Free Gaza Movement.
The Free Gaza Movement, which called the people human rights workers, said that "after full day in court" the four were ordered held until June 8.
It said they face "multiple serious criminal offenses for their participation in a peaceful voyage to break Israel's blockade of Gaza."
Early Monday, Israeli commandos conducted a raid on the ships in the flotilla and a fight on one of the ships led to nine deaths. The activists on the ship said they were attempting to deliver aid to Gaza and break Israel's military blockade. Israel, concerned that weapons are being shipped to militants in the Hamas-run territory, controls aid distribution to the people in the territory.
The four people are Free Gaza Movement board director Lubna Masarwa; Sheik Raed Salah, leader of the northern branch of the Islamic Movement in Israel; Mohammed Zeidan, director of the International Advocacy Programme for the Arab Association for Human Rights, and Sheik Hamed abu Dabis, the head of the southern branch of the Islamic Movement in Israel.
Adalah, which describes itself as "The Legal Center for Arab Minority Rights in Israel," said Judge Dina Cohen of the Magistrates' Court in Ashkelon extended the detention after a nine-hour hearing Tuesday and the group plans to appeal the remanding in district court Thursday.
"While no indictment has been issued, the state argues that a range of criminal offenses could apply, including conspiracy to commit an offense, and possession and use of weapons," the group said.
The defense attorneys said the state doesn't have evidence to prove that the four participated in the violence, and they said Israel has no jurisdiction in the case since the ship was in international waters at the time of the raid.