Picture used for illustrative purpose only.

A breakthrough has been reached in Qatar's three-year-old with Saudi Arabia and three other Arab countries and an agreement to end their rift is to be signed in Saudi Arabia on Tuesday, a senior Trump administration official said.

"We've had a breakthrough in the Gulf Cooperation Council rift," said the official.

Under the agreement, Saudi Arabia, UAE, Bahrain and Egypt will lift blockade of Qatar, and Doha will drop related lawsuits.

Saudi Arabia to open airspace, borders to Qatar, Kuwait minister said.

Qatar said on Monday that its emir would attend a summit of regional leaders.

"The Emir of the country is heading the delegation of the State of Qatar to participate in the meeting of the... Gulf Cooperation Council" that starts on Tuesday, Sheikh Tamim Bin Hamad Al Thani's office said in a statement.

According to Associated Press, the White House senior adviser Jared Kushner helped negotiate the deal and was working the phones on it until the wee hours of Monday morning, the official said.

Anwar Gargash.

UAE Minister of State for Foreign Affairs Anwar Gargash said in a Twitter post that "more work lies ahead and we are moving in the right direction."

Dr Gargash said, “We are before a historic summit par excellence in Al-Ula, through which we will restore Gulf cohesion. We are keen to ensure the security, stability and prosperity of our countries and people are the first priority. We have more work to do and we are in the right direction.”

Kuwait has been mediating between Qatar and the four Arab states.

The lifting of the embargo by Saudi Arabia paves the way for Qatar's ruler to attend a summit of Gulf leaders on Tuesday that will be held in the kingdom's desert city of Al-Ula and chaired by the Saudi King Salman.

Summit for Unity

The Gulf Cooperation Council summit will be "inclusive,” leading the states toward "reunification and solidarity in facing the challenges of our region,” Saudi Crown Prince Mohammed Bin Salman was quoted as saying in remarks carried by the Saudi state-run news agency.

Prince Mohammed Bin Salman.

The decision by the close US allies comes in the final days of the Trump administration's time in office, and just ahead of President-elect Joe Biden's swearing in.

Prince Mohammed Bin Salman Bin Abdulaziz, Crown Prince, Deputy Prime Minister and Minister of Defence announced that the policy of the Kingdom of Saudi Arabia, under the leadership of the Custodian of the Two Holy Mosques King Salman Bin Abdulaziz Al Saud, is based on a solid approach targeting achieving the ultimate interests of the Gulf Cooperation Council (GCC) member states and the Arab countries, in addition to harnessing entire endeavors for the good of their peoples and to realise their security and stability.

Crown Prince reasserted that the upcoming GCC summit shall be a summit to close the ranks and unify the stance and to enhance the march of the good and prosperity, adding that we will translate through the summit, the anticipations of the Custodian of the Two Holy Mosques and the leaders of the GCC member states, in order to gather and be in solidarity to face the challenges our region is witnessing.

Crown Prince prayed that may the High and Far Exalted Allah perpetuate the GCC member states' security and stability and the cohesion and solidarity among their peoples.