The accusation of financing terrorism levelled by some [Persian] Gulf countries against Qatar has "no solid base" , he said in an interview with the Charlie Rose show on PBS.
Sheikh Hamad bin Jassim demanded the countries that cut off relations with Qatar should provide evidence of their allegations.
The former Prime Minister demanded that international law should tackle the violations, including cutting off food supplies, separating families and closing of airspace, made by the countries that have isolated Qatar .
He expressed surprise at the position taken by Saudi Arabia and others soon after the participation of the Emir Sheikh Tamim bin Hamad al-Thani in the Riyadh Summit.
On Syria, Sheikh Hamad bin Jassim said everybody including the US made mistakes while dealing with the crisis in that country. "As time passed we discovered that some groups have other agendas and we stopped dealing with them one after another." He stressed that these mistakes were not intentional.
He pointed out that the punitive measures against Qatar were taken without convening the [Persian] Gulf Co-operation Council (GCC).
"If Saudi Arabia disagrees with any country, they will do what they want without referring to the GCC," he said adding that he respected King Salman and Saudi Arabia, but the new situation has changed many things for the members of the GCC.
On Qatar's alleged support for Iran, Sheikh Hamad bin Jassim said: "This is a big joke," stressing that there was not a single incident where Qatar supported Tehran. He added that the Qatar has normal relations with Tehran. He said Qatar is ready to hold an open dialogue if the problem is related to Iran.
On the presence of some members of the Taliban movement in Qatar, he said that there are five Taliban members, who are in Qatar at the request of the US.