Over a thousand Arab Israeli protesters massed in the northern city of Haifa on Friday evening to rally against the IDF’s ongoing ground incursion in the Gaza Strip. The demonstrators, led by controversial Balad MK Hanin Zoabi, clashed with police as they attempted to block several roads in the coastal city.

A number of police officers and protesters, among them Balad MK Jamal Zahalka, who also took part in the rally, were lightly injured and received medical treatment at the spot.

Some of the protesters were reported to have waved Palestinian flags as they chanted slogans welcoming Hamas rocket fire at Tel Aviv. The demonstrators also shouted out slogans against Palestinian Authority President Mahmoud Abbas and Prime Minister Benjamin Netanyahu.

Thirty protesters were arrested, including Zoabi, who was handcuffed by police officers at the site. The Balad MK was released from police custody a short while later.

Police maintained the rally was unauthorized as the demonstrators had failed to alert authorities of its existence.

“The demonstration was not approved, it is illegal,” Police Coast District Commander Hagai Dotan said. “Demonstrations today are organized through posts on Facebook and are hard to prevent, but we’ll explain the situation to the rioters.”

Protests were also held in Acre, Tamra, and Arab Israeli communities in the Wadi Ara area.

“The Israeli government is not just conducting a war, it is committing war crimes and crimes against humanity,” former MK Taleb el-Sana told Ynet reporters during an interview following the demonstrations.

“The Israeli government’s goal is to collect blood from the Palestinians.”

Earlier Friday, the northern branch of the Islamic Movement organized a mass prayer session in the Arab Israeli town of Kfar Kara in solidarity with the Palestinians in Gaza. The chairman of the northern branch, Sheikh Raed Salah, spoke after the session and urged Arab leaders to intervene in order to bring about an immediate ceasefire.

Protests in Kfar Kara are expected to resume Saturday as well.