The Free Gilad Schalit campaign stepped up activism in advance of the kidnapped soldier's 23rd birthday on Friday, with four activists arrested after hundreds of protesters gathered Tuesday outside three prisons in order to block Palestinian security prisoners' families from visiting their inmate relatives. Hours after Schalit's family and friends joined in the protests, a Hamas spokesman hinted for the first time that some progress could be expected toward the release of the tank gunner who has been held in the Gaza Strip for more than three years. As a senior Hamas delegation led by Mahmoud Zahar arrived in Egypt for negotiations, Hamas spokesman Ayman Taha said that the recently revealed German involvement in the negotiations between Israel and Hamas for Schalit's release has helped advance a deal. "There is movement in the talks, but there still has not been a real breakthrough that will bring about the release of the captured soldier," Taha said. Army Radio reported that in addition to the Egyptian-brokered discussion slated to pave the way to a cease-fire between Fatah and Hamas, Palestinian sources said it is likely that the negotiations for Schalit's release will also be discussed. Prime Minister Binyamin Netanyahu, who refused to speak about Schalit in London on Tuesday, is expected to receive a briefing from German officials about their efforts to free the IDF soldier during the prime minister's visit to Berlin on Wednesday. Earlier on Tuesday, hundreds of activists gathered outside the Meggido, Hadarim and Shikma prisons and attempted to block the special buses that ferry the Palestinian families from the West Bank to the Israel Prisons Services-run facilities. The protesters expressed frustration that Hamas has not allowed anyone - including humanitarian officials - to visit the IDF soldier, who has been held in Gaza since June 2006, while Palestinian terrorists in Israel enjoy regular family visitations. Protesters succeeded in blocking one bus and two minibuses, but all three were eventually released to continue on their way after police dispersed the activists. The four arrested, including prominent activist Magen Dahari, were accused of trying to obstruct traffic on Route 4 outside the Hadarim jail, near the busy Bet Lid junction. The activists chanted, "We want Gilad" and "Hamas will not enter." Gilad's father, Noam, joined activists at Meggido prison. He said it was "unacceptable" that his son was being refused visits, while the families of Palestinian prisoners saw their incarcerated relatives "all the time." He added that he hoped the latest round of protests would "achieve results and percolate upwards," and said it was "important that the Israeli public made its voice heard." "Unlike Noam, I am not here to calm things down. I am here to light them on fire," Miki Goldwasser told a cheering crowd. Goldwasser's son Ehud was one of the two IDF reservists who were kidnapped near the Lebanese border 17 days after Gilad Schalit was taken, and whose bodies were returned last year as part of a prisoner exchange. Protesters demanded - and were permitted - to distribute flyers to prisoners' family members in which the Palestinians were told: "You have come to visit your loved ones, and we are not letting you get off of the bus. We are here in the name of Gilad Schalit, because he also wants to receive a visit." In response to the pamphlets, at least one visitor - a father of a prisoner from Tulkarem - told Israel Radio that he identified with the activists, and that a solution involving a prisoner swap must be reached. One prisoner's father leaned out the window of a bus to shake Noam Schalit's hand and express his empathy. In an attempt to avoid friction with the activists, the Prisons Service had canceled family visits for Palestinian security prisoners at three facilities - Adumim Prison, near Ra'anana, and Shikma Prison in Ashkelon, but left visits at both Hadarim, in Tel Mond, and Meggido, in the Galilee, as planned. The move earned the ire of at least one organization. Moked: The Organization for the Rights of the Individual fired off an angry letter to Prisons Service Chief Warden Benny Kaniak, arguing that his decision to also prevent family visits to Hadarim Prison and Gilboa Prison, in the Galilee, following the protests "harmed people who are weak and voiceless in the Israeli public. "Instead of canceling the visits, which is the easy step, the IPS and police should have prevented the protesters from attempting to stop the visits," wrote attorney Daniel Shenhar. On Wednesday, the Schalit family will take a brief respite from the activism surrounding Gilad's fourth birthday in captivity in order to see off their youngest child, 19-year-old Hadas, who is enlisting in the IDF. The Schalit family has emphasized that they raised all three of their children to serve their country, and it appears likely that their daughter will serve in Gilad's Armored Corps brigade as a social welfare noncommissioned officer.