US Secretary of State John Kerry on Wednesday said Israeli and Palestinian leaders have reached a pivotal point and it was now up to them to make important decisions that will lead to lasting peace. Kerry arrived in Boston from a one-day visit to the Middle East that included discussions with Israeli Prime Minister Benjamin Netanyahu and Palestinian President Mahmoud Abbas. "We are very concerned about the violence and the potential for the situation to spin out of control," Kerry told reporters. "I think we may be reaching a pivotal point now where both sides have important decisions to make for the future, and we obviously hope they make choices that will advance the prospects for lasting peace," he said before leaving for the long US Thanksgiving holiday weekend. Kerry added that the United States has been encouraging both sides to take "affirmative steps" to reduce tensions and show genuine commitments to a two-state solution. Kerry described a wave of Palestinian knife and car-ramming attacks as "acts of terrorism" that must be condemned. On Tuesday, a Palestinian drove his car into three Israeli soldiers and a paramilitary border policeman along a road in the Israeli-occupied West Bank, injuring all four, the army said. It was the latest incident in nearly two months of knife, gun and car-ramming attacks by Palestinians. Israeli medics said they were treating and evacuating to hospital a 20-year-old in serious condition with stab wounds to his torso. The attacker was also being transported to hospital. In his talks with Kerry, Netanyahu told him that civilian Palestinian projects would be allowed to advance only when Israel experienced a "return of the quiet," an Israeli official said. The premier also conditioned Palestinian construction in Israeli-controlled parts of the West Bank on international recognition of Israel's right to build in existing settlement blocs. The United States rejected the notion of settlement recognition with "a big no," a State Department spokesman said. Jewish settlements in the occupied West Bank are seen as illegal under international law and major stumbling blocks to peace efforts since they are built on land Palestinians see as part of their future state. "Every US administration since 1967, Democrat and Republican alike, has opposed Israeli settlement activity beyond the 1967 lines, and this administration's been no different and will be no different," State Department deputy spokesman Mark Toner said. Kerry at the same time expressed strong support for Israel and condemned Palestinian attacks when he met Netanyahu. In brief remarks after meeting Abbas in Ramallah, Kerry also expressed sympathy for the Palestinians' "very dire" situation and concerns "about the violence," while stressing US commitment to a Palestinian state. — Agencies