US ambassador Dan Shapiro on Monday charged that Israel seems to apply separate "standards" of justice for Israelis and Palestinians, drawing a rebuke from Prime Minister Benjamin Netanyahu. "Too much (Jewish) vigilantism goes unchecked, and at times there seems to be two standards of adherence to the rule of law, one for Israelis, and another for Palestinians," Shapiro said in a speech at the annual meeting of the Institute for Strategic Studies in Tel Aviv. The ambassador welcomed the indictment in early January of two Israelis over a firebombing in the occupied West Bank last year that killed a Palestinian couple and their toddler. The indictments were "an important demonstration of Israel's commitment to prosecute acts of terrorism, regardless of their source, but too many attacks on Palestinians lack a vigorous investigation or response by Israeli authorities," he said. Netanyahu's office insisted the Jewish state "applies the law on Israelis just as it does on Palestinians" and said Shapiro's comments — coming on the same day as the burial of an Israeli mother of six who was stabbed to death in her home in a West Bank settlement — were "not acceptable or just." In the West Bank, Israelis are subject to Israeli civil law, while Palestinians are governed by Israeli military law, which offers far fewer legal protections. Palestinians and rights groups say that Israelis suspected in violence against Palestinians are rarely brought to justice, while Palestinian attackers are quickly arrested or killed. The Israeli human rights group Yesh Din said Shapiro's comments were grounded in data they have been collecting that showed an 85 percent failure rate in investigating ideologically-motivated crimes by Israelis against Palestinians. Over the past decade, the group says it has monitored the police's handling of 1,104 investigations opened following complaints of Palestinians. It says indictments were served against suspects in just 75 of these cases. The US ambassador to Israel also criticized Israel's West Bank settlement policies. Daniel Shapiro said that Washington was "concerned and perplexed" over Israel's strategy of building West Bank settlements. Speaking to the annual conference of the Institute for National Security Studies, a top Israeli think tank, he said Israel's continued expansion of settlements raises questions about Israel's intentions and its stated commitment to establishing an independent Palestinian state. Shapiro added that Israel had also legalized some West Bank outposts despite pledges to the United States not to do so. As Israel's closest friend, the United States is steadfast in its support for Israel but it was also its role to call Israel out on its errors, Shapiro said. He noted that Israel restricts Palestinian economic development in the West Bank and, despite its recent indictment against the suspects in a deadly arson attack against a Palestinians family, bemoaned what he called an inadequate response to settler violence. The international community considers the settlements, built on lands Israel captured in the 1967 war and claimed by the Palestinians, illegal or illegitimate. The spat highlights the tense relations of late between the United States and Israel, mostly over Israel's fierce objection to the Iranian nuclear deal.