The chairman of Germany’s main opposition party has accused Israel of running an “apartheid regime” in Hebron.

“I was just in Hebron. There’s a legal vacuum there for Palestinians. This is an apartheid regime, for which there is no justification,” Sigmar Gabriel – who has a good chance of becoming Germany’s next chancellor – posted on his Facebook wall. The post quickly drew hundreds of responses, mostly from pro-Israel surfers, some of whom threatened to cancel their memberships in the SPD, the party that Gabriel leads.

Gabriel then clarified his remarks in two follow-up posts, saying that he didn’t mean to compare Israel with South Africa’s apartheid regime but that he is “immensely angry” about how Palestinians are treated in Hebron.

“I think [Israel’s] current settlement policy is wrong and I consider the conditions [in Hebron] undignified,” wrote Gabriel, who is widely expected to challenge chancellor Angela Merkel in next year’s national elections. “We are not doing any favors to us or our friends in Israel if we continue veiling our criticism in diplomatic flowers of speech.”

Gabriel, who has been to Israel about 20 times, added that the situation for Palestinians in Hebron is “indeed terrible.” Even Israeli soldiers he met there told him they find the conditions “unbearable,” he wrote. Israel has the right to defend itself, as it is the only state in the world whose neighbors question its right to exist and whose citizens suffer daily from rocket attacks, the 52-year-politician added. “But that is no justification for continuing with a settlement policy such as the one that can be witnessed in Hebron. It shouldn’t lead to us prohibiting ourselves from criticizing the errors of the Israeli government.”

In a second post, Gabriel answered his critics who were offended by him speaking of Israel as an apartheid regime. “I am aware that this a very drastic term. But that’s exactly how the Palestinians in Hebron see their situation. That drastic term is what came to my mind during the talks and visits in Hebron.” Gabriel then clarified that he did not mean to compare Israel with apartheid South Africa, as that would be “more than unfair” to the Jewish state. “But the humiliating way Palestinians are dealt with in Hebron exceeds much of what one is used to from the West Bank. And this makes even someone like me, who supports Israel, immensely angry.”

Gabriel, who during his current Middle East trip met with Prime Minister Benjamin Netanyahu and Palestinian Prime Minister Salam Fayyad, earlier this week said that he wants Israel to engage in dialogue with Hamas. He had planned to meet with a representative of the terror group but canceled due to the recent cross-border violence between Israel and Gazan terrorists.

“Hamas is a factor in this conflict. And you can’t solve a conflict if one factor is being ignored,” Gabriel told reporters in Jerusalem. He also said that he fully supports the Palestinians’ efforts to have Palestine accepted as a member state of the United Nations, “because there is no counterargument to that.”