By Rania El Gamal and Raissa Kasolowsky

KUWAIT, Dec 15 (Reuters) – Gulf Arab countries endorsed a monetary union agreement on Tuesday despite the absence of major player the United Arab Emirates and fellow oil producer Oman and left options open for pegging their future single currency.

Rulers from the world’s top oil exporting region gathered in Kuwait to push forward the much-delayed project, whose viability was put in question by the pullout in May of the UAE, the second largest Arab economy after Saudi Arabia.

The central bankers from four states in the union — Saudi Arabia, Kuwait, Qatar and Bahrain — will now set a timetable for the creation of a joint central bank, Kuwait’s finance minister said, but the summit revealed no details on what authority its forerunner would have.

Kuwaiti Finance Minister Mustapha al-Shamali expressed hope the UAE and Oman would rejoin the planned union in the near future, but did not give more details about his country’s drive to secure their return during its 2010 presidency of the Gulf Cooperation Council.

Kuwait said on Monday no specific deadline has been set for the launch of the planned single currency, which officials have said could take up to 10 years.