"The Qatari people and us are one people".
"Enough is enough", he added.
On Tuesday a spokesman for the forces of Libyan military strongman Khalifa Haftar, Ahmad al-Mesmari, speaking at a press conference in Cairo, accused Qatar along with Turkey and Sudan of supporting "terrorist groups" in Libya. More than two weeks after the onset of the crisis, the countries issued a list of 13 demands that Qatar, a tiny energy-rich emirate, was required to meet within 10 days.
Qatar has consistently rejected those allegations and already indicated it would not comply with the demands, saying they were so extreme they seemed deliberately created to be rejected. That period expired Sunday night, but it was extended for 48 hours.
The Qatari foreign minister had earlier made a statement explaining Qatar's stand in the rift with the four Arab neighbours, although envoys have been working hard to tackle the crisis that has spawned diplomatic tensions throughout the region.
Its foreign minister, Sheikh Mohammed bin Abdulrahman al-Thani, said the stiff demands, which include ejecting Turkish troops based there, would be rejected. Kuwaiti and Qatari officials did not respond to questions about what the letter said, though a photograph from the meeting showed Sheikh Sabah reading it with no expression on his face.
"We are still waiting for the response from our brothers in Kuwait regarding the paper they received from Qatar", the Emirati foreign minister said.
Among the potential further steps the countries could take against Qatar would be to suspend it from the six-nation Gulf Cooperation Council (GCC), which is closely allied to the United States.
Before his trip, Gabriel had said he meant to remain neutral in the dispute with Qatar, but stressed that stability in the region was also a matter of global interest. A defiant Qatar has claimed the demands were deliberately "made to be rejected". "We are trying to act mature and discuss the matter".