HE the Deputy Prime Minister and Foreign Minister Sheikh Mohamed bin Abdulrahman al-Thani on Thursday participated in a meeting to support peace in the Middle East being held in the Polish capital Warsaw.

The meeting is discussing issues related to the war in Syria, the Yemeni conflict and the peace process between Palestinians and Israelis.

However, a Palestinian official said in remarks published on Thursday that the conference jointly organised by US President Donald Trump's administration lacks credibility as it aims to "normalise" the Israeli occupation of Palestinian territory.

"By fully siding with the Israeli government, (the Americans) have tried to normalise the Israeli occupation and the systematic denial of the Palestinian right to self-determination," Nabil Shaath, an adviser to Palestinian President Mahmud Abbas, wrote in a column published by Israel's Haaretz newspaper.

But Trump's son-in-law, Jared Kushner, is expected to offer hints of the US administration's proposals for peace between Israel and the Palestinians.

Shaath said the Palestinians had refused to go to the conference.

"The Warsaw conference is part of this context," he wrote.

"A peace process cannot be turned into an attempt to obtain amnesty for war crimes or to make one of the parties surrender its basic rights under the UN charter."

The Palestinians have refused to talk to the Trump administration since the US leader recognised Jerusalem as Israel's capital in December 2017.

The Trump administration has since dealt a series of harsh blows to the Palestinian Authority, including cutting hundreds of millions of dollars in aid to Palestinians.

The two-day conference is officially devoted to security in the Middle East, with a strong emphasis on Iran.

But Iran's President Hassan Rouhani dismissed the talks as producing an "empty result," after Washington called on European allies to toughen their policy on Tehran.

"We see what's happening in Warsaw, it's an empty result, nothing," Rouhani said during a press conference in the southern Russian city of Sochi where he met with Russia and Turkey leaders to discuss Syria.