Israel has arrested two Palestinian political activists and accused them of security breaches, including contact with the Lebanese resistance movement Hezbollah.
Israeli police arrested Ameer Makhoul in early May and Omar Said in late April, both without charge, AFP reported.
Makhoul is the director of a group representing Arab NGOs in Israel and Said is a member of the Arab political party Balad.
Israel’s domestic security agency Shin Bet said they were suspected of "severe security offences, including contacting a Hezbollah agent,” the British newspaper The Guardian reported on Monday.
A court order had banned any disclosure regarding the captures until Monday.
The Israeli website Ynetnews said the Legal Center for Arab Minority Rights in Israel has challenged the arrests.
"The charge of ‘contacting an enemy agent’ is a generic offense that the Shin Bet can use to frame any Arab who upholds legitimate contacts with social or political activists in the Arab world," Ynetnews quoted a statement by the center as saying.
Several Arab human rights groups have issued a petition protesting against the arrests.
"In addition to arbitrary arrests and detentions, Israeli authorities have met Palestinian human rights activism in recent months with a variety of measures, including raids, deportations, travel bans, visa denials, and media attacks," AFP cited the petition as saying.
About 300 people rallied in the city of Haifa later on Monday, calling for their release.