Saudi Arabia's King Salman has invited Qatar's Emir Sheikh Tamim bin Hamad Al Thani to attend the upcoming Gulf Cooperation Council (GCC) summit set to take place in Riyadh on December 9, the official Qatar News Agency reported.

The announcement on Tuesday follows Qatar's decision a day earlier to withdraw from the Organisation of Petroleum Exporting Countries (OPEC), a move seen by some analysts as deeply symbolic given Qatar's modest oil output.

Qatar News Agency (QNA) said in a tweet the emir received "an invitation from the King of Saudi Arabia" for the meeting. 

The invitation was delivered by the Bahraini secretary general of the GCC, Abdullatif bin Rashid Al Zayani, during a reception by Qatar's Minister of State for Foreign Affairs Sultan bin Saad Al Muraikhi. 

QNA did not say if Sheikh Tamim would travel to Saudi Arabia.

A quartet of Arab states, composed of Saudi Arabia, the United Arab Emirates (UAE),Bahrain, as well as non-GCC member Egypt, imposed a land, sea and air blockade on Doha in June 2017.

The Saudi-led bloc accuses Doha of abetting "terrorism" and contributing to instability in the region, allegations Qatar has categorically denied.

At last year's GCC summit, held in Kuwait, Saudi Arabia, the UAE and Bahrain sent ministers or deputy prime ministers, rather than heads of state.

Kuwait, which has been mediating between Qatar and the bloc, said last month all six GCC member states were expected to attend the Riyadh summit.

"I am optimistic that the level of representation is expected to be high and reflects the keenness of GCC leaders to maintain this pioneering experience," Kuwaiti Deputy Foreign Minister Khaled Al-Jarallah was quoted as saying at the time. 

A political and economic alliance shaped after the European Union, the GCC took a hard hit after the quartet cut off relations with Doha.

The United States, a GCC ally, has also tried to mediate in the Gulf dispute, which it sees as a risk in its efforts to contain regional power Iran. Qatar is home to the largest US airbase in the Middle East.

But Saudi Arabia and the UAE have repeatedly said resolving the dispute was not a top priority for them.

The diplomatic crisis over Saudi journalist Jamal Khashoggi 's killing, however, has put pressure on Riyadh.

Following Khashoggi's killing, Saudi Crown Prince Mohammed bin Salman (MBS) last month praised Qatar's economy in a rare conciliatory remark.