GAZA (Reuters) - A Palestinian Liberation Organisation faction said on Thursday it would not attend a meeting of the most important Palestinian political congress in years, because it wants more factions to be included.

The Popular Front for the Liberation of Palestine (PFLP) said it will boycott the rare Palestinian National Council (PNC) session, after a delay to allow such factions as Hamas and the Islamic Jihad to attend was not been granted, the group said in a statement issued in Cairo on Thursday.

The PFLP is the second-largest PLO faction after Fatah, the group headed by Palestinian President Mahmoud Abbas, who also heads the PLO. Its absence would be a blow to his efforts to win a broad consensus on resolutions.

“The PFLP’s decision will lead to weakening the legitimacy of the PNC meeting and the legitimacy of decisions it may take,” said Hani Habeeb, a Gaza political analyst.

The 700-member council session will convene in the West Bank town of Ramallah on April 30 to discuss U.S. President Donald Trump’s recognition of Jerusalem as Israel’s capital, a U.S. policy change that has outraged the Palestinians.

Trump’s announcement and the planned move in May of the U.S. embassy to Jerusalem reversed decades of U.S. policy on the city, whose status is one of the main obstacles to reaching a peace agreement.

Palestinian leaders said Trump’s Dec. 6 declaration meant that Washington could no longer take the lead in Israeli-Palestinian peace efforts, which have been frozen since 2014.

In Ramallah, Fatah spokesman Osama Al-Qawasmi said the PNC session would be held as planned.

“We hope they will revise their position so that we can together face the difficult stage in the face of Trump’s ‘deal of the century’ so that we can cement an internal front,” said Qawasmi.

The PNC last met in 2009 in what was termed an emergency session. That meeting was held to replace six of the 18 members of the PLO executive committee, the Palestinians’ highest decision-making body.

It last held a regular session in 1996 in the presence of then-U.S. President Bill Clinton when it voted to amend clauses in the PLO’s charter that advocated Israel’s destruction.

The last Palestinian general election was held in 2006, when the Hamas Islamist movement trounced Abbas’s Fatah. A unity government collapsed, and in a brief, bloody civil war in 2007, Hamas seized the Gaza Strip from forces loyal to Abbas.