Police are considering criminal charges against the organizers of what they claim was an unauthorized demonstration Thursday afternoon to commemorate the second anniversary of the evacuation of 21 Gaza Strip settlements. Lachish Subdistrict police said they were trying to engage in dialogue with protest groups to better prepare for other events in the Gaza Strip periphery expected in the coming weeks. Thursday afternoon, the Israel Police seemed to be caught off guard as a group of approximately 500 right-wing activists and former Gaza settlers gathered at Yad Mordechai junction with the aim of marching toward the evacuated Northern Gaza settlements of Nisanit and Alei Sinai. More than 200 police officers - including border policemen, the Yasam reconnaissance unit and mounted police - were deployed to the area. Twenty-one people were arrested when confrontations erupted between protesters and police, who formed a human chain to block marchers from advancing past Netiv Ha'asara. During the protest some of the youths snuck unnoticed to nearby hillocks and four of them scaled the security fence to enter the Gaza Strip. Police said the IDF informed them that some Israelis had crossed the barrier. Troops from the Golani Brigade "rescued" the infiltrators a few dozen meters beyond the security fence and brought them back to the Israeli side of the fence. The "March to Nisanit" was held as part of the second anniversary commemoration of the disengagement plan's implementation. National Union MKs Uri Ariel and Arye Eldad and Safed Chief Rabbi Shmuel Eliyahu participated in the three-kilometer march. "Today we express our demand for the right of return," Eldad said, addressing the marchers. "Anyone who thinks that we will forget the homes from which Gaza residents were evicted, is deluding himself. Hundreds of youths are declaring that mistakes can be amended and are demanding to return home." Ten minutes after buses carrying the protesters left the Netiv Ha'asara area, two mortars landed meters away from where they had gathered. Police and the detainees were still at the scene. One officer said the mortars landed only a few meters away from police. Police said they had been told that the marchers intended to hold similar protests every Thursday, but said they did not know of specific plans to commemorate the pullout.