The quartet presented in late June a list of 13 demands to Qatar as preconditions for resuming diplomatic ties and ending their sanctions. The demands included Doha's end to funding terrorism and extremism, stoping interference in their internal affairs and downgrading ties with Iran.

For its part, Qatar has strongly denied the charges, while rejecting the the quartet's demands, citing it would not negotiate on issues related to its sovereignty.

On Sunday, the quartet's foreign ministers also stressed that Doha must honor the six principles put forward by them during their previous meeting in Cairo, Egypt earlier the month.

The six principles, a reduced version of the 13 demands, include demands for Qatar to stop funding terrorism and extremist groups, stop inciting propaganda against them and halt interfering in their internal affairs.

They were created amid signs of easing of the Gulf standoff following the visit to the region by US Secretary of State Rex Tillerson earlier the month.

During Tillerson's visit, Qatar and the US signed a deal on combating terrorism financing, one of the core demands by the Saudi-led alliance.

Later, Qatari Emir Sheikh Tamim bin Hamad Al Thani issued a decree to amend some provisions of its law on fighting terrorism.

On July 21, in his first public speech since the crisis started, Sheikh Tamim also called for holding talks to resolve the Gulf standoff, though emphasizing that any talks should respect its national sovereignty.

He insisted that his country has been "fighting terrorism relentlessly and without compromise."