Israeli security forces gather at the scene where an Israeli died and three of his relatives were wounded after a Palestinian gunman opened fire on their car on July 1 in the occupied West Bank. (Hazem Bader/AFP/Getty Images)

The potential for a two-state solution to decades of conflict between Israelis and Palestinians is steadily eroding, members of the Middle East Quartet mediation group said Friday in a report aimed at nudging the parties back to peace talks.

The report, delayed several times as the final language was refined, calls on the Israelis to cease the construction and expansion of settlements, the designation of land exclusively for use by Israelis and the denial of development permits to Palestinians. It also recommends that Palestinian authorities stop inciting violence and work harder to combat terrorism, such as by clearly condemning all acts of terrorism.

The Quartet, the sponsor of a peace process that has gone nowhere since collapsing amid mutual recriminations in April 2014, is composed of the United Nations, United States, Russia and the European Union. The imprimatur of the United States, Israel’s closest ally, adds extra weight to the report, but it is more of a road map for talks to resume rather than a mandate.

“We’re trying to provide them with a constructive path forward should they choose to take it,” said a State Department official, speaking on the condition of anonymity under the agency’s rules. “That’s ultimately up to them.”

Initially, at least, the parties weren’t changing their long-held stances.

“The report perpetuates the myth that Israeli construction in the West Bank is an obstacle to peace,” Israeli Prime Minister Benjamin Netanyahu said in a statement. “When Israel froze settlements, it did not get peace. When Israel uprooted every settlement in Gaza, it did not get peace. It got war.”

Palestinian officials also bristled at the report’s conclusions.

“It does not meet our expectations as a nation living under a foreign colonial military occupation,” said Palestine Liberation Organization General Secretary Saeb Erekat.

But Quartet members warned that the window for a solution is closing.

“We need to shake life back into the peace process, and do it as a matter of urgency,” said Federica Mogherini, the foreign policy head of the E.U. “Violence is on the rise every single day, with victims of both sides. We risk a new escalation, and the very chance of peace is slipping away.”

The Quartet said two states, one Israeli and one Palestinian, is the only way to end the occupation and ensure Israeli security. But Israeli policies encouraging settlement growth and squelching Palestinian development are “steadily eroding the viability of the two-state solution,” it said.

The report was released amid a new spate of violence in Israel and the West Bank. In separate attacks over the past few days, two Israelis were killed and five were injured. Three Palestinian assailants were also killed.

The report criticized Palestinian incitement to violence and the Palestinian society’s glorification of those who attack Israelis as “heroic martyrs.” It blamed Hamas and other radical factions for most of the incitement.

“Regrettably, however, Palestinian leaders have not consistently and clearly condemned specific terrorist attacks,” it said.

Eglash reported from Jerusalem.