United Nations, June 25 (RHC)-- A "watershed moment" that will constitute a "most serious violation of international law" -- that is how United Nations chief Antonio Guterres has described Israel's plans to annex parts of the occupied West Bank and Jordan Valley.

Addressing a virtual meeting of the UN Security Council on Wednesday, Guterres repeated a call for Israel to drop its United States-backed plans, which could be put in motion as soon as next week.

If implemented, the UN secretary-general said, annexation would "grievously harm the prospect of a two-state solution and undercut the possibilities of a renewal of negotiations."

"I call on the Israeli government to abandon its annexation plans."  Guterres's call was echoed by other leaders and foreign ministers addressing the virtual meeting, warning that Israel's unilateral action could trigger a major escalation in the region.

"For three decades, real peace and the creation of an independent Palestinian state, remain elusive ... Despair is dominating the Palestinian mood and scene,"  Arab League chief Ahmed Aboul Gheit said.

Wednesday's meeting is seen as the last international one before Israeli Prime Minister Benjamin Netanyahu's right-wing government starts planned discussions on July 1st over the annexation of the West Bank, territory Israel captured in a 1967 war and that Palestinian leaders seek for a future state.

At the UNSC meeting, Nickolay Mladenov, the UN peace envoy for the Middle East, warned of the legal, security and economic implications of such a move.

"Annexation could irrevocably alter the relation of Israeli-Palestinian relations. It risks upending a quarter of a century of international efforts and support of a future viable Palestinian state," Mladenov said.

"Today, we are further than ever from this goal [of a two-state-solution]."  Mladenov noted that international condemnation has also been widespread, including the European Union's stark opposition to the slated plan.

On Wednesday, more than 1,000 parliamentarians representing 25 European countries signed a letter denouncing Israel's plans, urging their leaders to prevent the annexation process and save the prospects of a two-state solution.

Palestinian Foreign Minister Riyad al-Malki warned any annexation would be a "crime" and lead to immediate and tangible repercussions.

He said Israel's objective has for decades been to grab "maximum Palestinian land, with minimum Palestinians". 

"Israel is testing the resolve of the international community, thinking that its colonial apartheid will prevail … We must prove it wrong," al-Malki told the council, calling on the international community to impose sanctions against Israel to deter its plans. 

Seven European nations -- Belgium, Britain, Estonia, France, Germany, Ireland and Norway -- in a joint statement warned annexation would "severely undermine" prospects for resuming the Middle East peace process.

"Under international law, annexation would have consequences for our close relationship with Israel and would not be recognized by us," they warned.

Al Jazeera's senior political analyst, Marwan Bishara, dismissed as lip service speeches by leaders addressing the Security Council, pointing to the lack of recommended actions.

"We all know who was the elephant in the room, we all know who is behind instigating this annexation ... did anyone point fingers at the United States?" Bishara asked.

"The reason this meeting has been called for is to send a message, that we are in dangerous territory ... But you would expect UNSC members and Arab League members to be taking a more firm stance."

While the U.S. was expected to give Netanyahu the official green light for his plan, U.S. Secretary of State Mike Pompeo said on Wednesday that extending Israeli sovereignty was a decision "for Israelis to make."

His comments came as U.S. Ambassador to the UN Kelly Craft told the council: "I understand that many of you have concerns with this issue of the potential extension of Israeli sovereignty in the West Bank … At the same time, we ask that you also hold the Palestinian leadership accountable for acts they are responsible for."

Unveiled in late January, U.S. President Donald Trump's so-called "Middle East plan," which strongly favours Israel and was rejected by the Palestinians,  gives Israel the green light to annex Israeli settlements and strategic areas of the occupied West Bank. 

The West Bank - including occupied East Jerusalem which Palestinian leaders want as the capital of their future state - is seen as occupied territory under international law, making all Jewish settlements there - as well as the planned annexation - illegal.

Palestinian officials have threatened to abolish bilateral agreements with Israel if it went ahead with such a move.

Trump's plan foresees the eventual creation of a demilitarised Palestinian state on the remaining patchwork of disjointed parts of the Palestinian territories without East Jerusalem.

The U.S. administration has declined to criticise annexation and rejected the consensus of most of the world that Israeli settlements on Palestinian land are illegal.

"Decisions about Israelis extending sovereignty to those places are decisions for the Israelis to make," Secretary of State Mike Pompeo told reporters in Washington.

Israel's UN ambassador Danny Danon criticised the Palestinians, saying the stalemate was due to their refusal to negotiate.

"Some in the international community choose to reward the Palestinians' rejectionism and ignore reality," he said.

Meanwhile, Guterres called on the Middle East Quartet of mediators - the US, Russia, the EU and the UN - "to take up our mandated mediation role and find a mutually agreeable framework for the parties to re-engage, without preconditions, with us and other key states".

Palestinians have protested against the potential move across the occupied territories this week, including the besieged Gaza Strip.

Al Jazeera's Nida Ibrahim, reporting from a protest on Wednesday in Jordan Valley, said senior Palestinian officials were expected to start gathering in a "symbolic" move to highlight that this is "Palestinian land." 

While Palestinians on the street do not have faith in the international community, Palestinian officials are committed to peacefully ending the Israeli occupation, Ibrahim said.

Anger has also surged among Palestinians following the deadly shooting of two Palestinians by Israeli soldiers this week.