German Foreign Minister Sigmar Gabriel said on Tuesday it would be "regrettable" if Prime Minister Benjamin Netanyahu called off a meeting between the two, as he threatened to do if the foreign minister met groups that have testified against Israel abroad.Gabriel, who has described Israel as an apartheid state, said it would be a "remarkable event, to put it mildly," if Netanyahu canceled their planned talks, arguing it was normal to talk to civil society representatives.Netanyahu issued an ultimatum to Gabriel the day before, saying that he will not meet with the German foreign minister if he holds his planned meeting with the NGO Breaking the Silence, which has testified to international organizations claiming that the IDF commits war crimes. A meeting with Gabriel was not on the prime minister’s schedule for Tuesday.Meanwhile, opposition leader Isaac Herzog (Zionist Union) took a different approach in a meeting with Gabriel in Jerusalem Tuesday, instead expressing his opposition to the organization's statements and approach, and presenting to Gabriel with his view on the IDF’s actions.“The IDF deals with terrorist threats in the most complex region in the world and, in all of Israel’s wars, has proven again and again that it acts according to the rules of international law, while protecting human rights, even when it puts the lives of soldiers in the field in danger by stopping actions out of concern for harming civilians in warzones who were often used by terrorists as human shields,” he stated.Herzog recounted the stabbing in Tel Aviv on Sunday by a Palestinian who was in Israel on an organized tour, with Israel’s permission, and a Palestinian woman who was allowed into Israel for cancer treatments, and smuggled in explosives with her medicines.In addition, the opposition leader talked about the need for a two-state solution and opportunities for Israel to expand ties with other countries in the region. Herzog also asked for Germany’s help to bring back the bodies of IDF soldiers Oron Shaul and Hadar Goldin, which have been held by Hamas in Gaza since 2014, as well as Abera Mengistu, an Israeli citizen Hamas is holding alive.Other opposition members continued criticizing Netanyahu’s likely snub of Gabriel.“Israel and the IDF have nothing to hide,” MK Tzipi Livni (Zionist Union) said. “The prime minister should be able to deal with [the NGOs’ claims] and give answers to any claim by any person or organization in Israel or abroad. That is what I do, and that is how we protect the IDF and Israel.”Meretz central committee President Uri Zaki, who used to head left-wing NGO B’Tselem’s American branch, said a member of the German delegation told him they would not give in to Netanyahu’s demands. Zaki said the ultimatum is “another step in the deterioration of democracy and the incitement that Netanyahu leads.”Netanyahu received support from Knesset Speaker Yuli Edelstein, who tweeted that Breaking the Silence and B’Tselem spread anti-Israel propaganda and called on Gabriel to cancel his meeting with them.Education Minister Naftali Bennett said his Bayit Yehudi party backs Netanyahu’s decision: “Breaking the Silence is not an anti-Netanyahu organization; it’s an anti-IDF one.”Former defense minister Moshe Ya’alon said: “I support the prime minister’s demand from the German foreign minister in connection to Breaking the Silence. The funding and involvement of Europe in these matters crosses redlines in relations between countries.”In 2012, during an election campaign, Gabriel called Israel an apartheid state. “This is an apartheid regime, for which there is no justification,” Gabriel wrote on his Facebook page.A surrogate for German Chancellor Angela Merkel called Gabriel’s comment “shameful” and said it “reveals Mr. Gabriel’s ignorance in foreign policy matters.”"Imagine if the Israeli Prime Minister ... came to Germany and wanted to meet people critical of the government and we said that is not possible ... That would be unthinkable," he told Germany's ZDF television.