The Palestinians plan to file the first war crimes case against Israel with the International Criminal Court on April 1, Muhammad Shtayyeh, a senior PLO official, said on Monday.The Palestinian case refers two issues to the ICC – Operation Protective Edge in the Gaza Strip, and Israeli settlement building – Shtayyeh told visiting US church leaders.Three “important steps” had to happen before the matter was settled, he said.The first step is this week’s meeting of the PLO leadership to decide on the future of relations between the Palestinian Authority (an organ of the PLO) and Israel, Shtayyeh said.The second is the March 17 election in Israel. US Secretary of State John Kerry on Friday called PA President Mahmoud Abbas and asked him to refrain from any “fateful” decisions until after the election.But the Palestinians don’t see a difference between the various competing parties, chiefly the Zionist Union and the Likud, Shtayyeh said.“None of them has a program for ending the occupation,” he said.“The [Isaac] Herzog and [Tzipi] Livni camp [of the Zionist Union] might show imaginary flexibility in appearance, while destroying its content,” he said.The third step involves filing a charge sheet against Israel with the ICC in April, Shtayyeh said.The ICC has accepted “Palestine” as a member state before the court, but the Palestinians can only act on that status as of April 1.But it is still unclear if they could file a case against Israel.On January 16, the ICC opened a preliminary investigation into “the situation in Palestine,” but it has yet to issue any findings.A government official in Jerusalem said that a decision by the PA to file a war crimes case against Israel in the ICC would be a “negative development in the extreme,” and would “compel Israel to respond.”The official did not say what the Israeli reaction would be. He noted that last week, the US district court in Manhattan, which he called an “objective court,” ruled “hands down” against the PA in a landmark case holding it responsible for terrorist acts during the second intifada.The US, along with the other members of the Middle East Quartet – Russia, the UN and the EU – are hopeful that a peace process can be resumed that would lead to two-state solution.The US has said in the past that an ICC suit would be counter-productive to those efforts.Shtayyeh on Monday complained that the Palestinian territories were undergoing an economic crisis that has seen a large rise in poverty and unemployment.He attributed the crisis to the failure of donor countries to fulfill their pledges to fund the reconstruction of the Gaza Strip, and the Israeli government’s decision to withhold tax revenues belonging to the Palestinians.High-level discussions are under way to more closely involve Arab states in the work of the Quartet and reinvigorate the group that has been seeking to mediate in the Israeli-Palestinian conflict since 2002.Rather than formally expanding the Quartet’s membership, the idea is to have more frequent top-level meetings with at least Saudi Arabia, Jordan and Egypt to ensure the region is better engaged at a time of tumultuous change, according to senior diplomats based in the Middle East and Europe.Federica Mogherini, the European Union’s foreign affairs chief, is expected to appoint a special envoy to the Middle East in the coming days. Officials said a first meeting of the Quartet along with Arab countries and perhaps the Arab League could take place in the coming weeks.Israeli-Palestinian peace talks collapsed in April last year after nine months of largely fruitless discussions sponsored by the United States.“The important thing is that there will be an outreach to those countries,” a European diplomat briefed on the proposals said. “There is an understanding that peace between Israelis and Palestinians must be embedded in a broader regional concept and for that you need neighboring Arab countries.“It’s very difficult to say at the moment what format this will take, because there are too many unknown factors.”No concrete plan is expected until after Israel’s election, but US and UN diplomats have made clear that they are open to the idea. It is not clear where Russia, long an outlier in the Quartet, stands.While Israel has not given the Quartet prominence in the past, preferring to have Washington lead negotiations, Prime Minister Benjamin Netanyahu has spoken of a need for a common approach with states in the region, especially given the rising threat from Islamic State.Robert Serry, the UN special coordinator in the region, said he would welcome enlargement of the Quartet, which he described as “leaderless.”“When the Quartet was having [its last] meeting on a high level, it was agreed that in any renewed Quartet activities to support the peace process, countries like Jordan, Egypt, Saudi Arabia and others need to be more closely associated,” Serry told Reuters.As well as those three states, officials have mentioned possible involvement of the United Arab Emirates or Qatar.Former British prime minister Tony Blair has served as the Quartet’s chief representative since 2007, and recent talk of him stepping down has been denied by officials close to him.They say he is committed to the role and has no plans to leave.Reuters contributed to this report.