A senior United Arab Emirates (UAE) official said global monitoring was needed in the standoff between Qatar and its Arab neighbours, adding he saw signs that the pressure exerted on Doha "was working".
"The Washington Post story today that we actually hacked the Qataris is also not true", he told the London-based think-tank Chatham House. "You will see in the next few days the story will die".
The Post reported that United States intelligence officials learned last week of newly analysed information that showed that senior UAE government officials discussed the planned hacks on May 23, the day before they occurred.
"The @washingtonpost story is false".
UAE Ambassador to the US Yousef al-Otaiba denied the report in a statement, saying it was "false", the Post said.
"What is true is Qatar's behaviour", he added.
Qatar's antagonists accuse it of supporting terrorism and giving a home to extremists inciting violence and radicalisation.
The report "unequivocally proves that this hacking crime took place", it added. Such statements are at odds with the prevailing sentiment in the Gulf. It added that the "crime" against its state news agency by a Gulf nation was a violation of worldwide law. Doha had previously asked U.S. and British officials to investigate the source of the hack.
Gargash's speech in London appeared to question Qatar's future in the GCC.
"This is our message: You can not be part of a regional organization dedicated to strengthening mutual security and furthering mutual interests, and at the same time undermine that security and harm those interests".
"You can not be both our friend and a friend of al-Qaeda".
Gargash also repeated accusations that Qatar was trying to create instability in the region and even accused it of conspiring with jihadists against Saudi Arabia.
Initially the USA seemed to have taken sides with them against Qatar in the dispute, President Trump accusing the Qataris of funding terrorism "at the highest level".
"We have some leads that there are some countries involved, part of them - they are part of the countries that will impose this blockade against Qatar", al Thani told CBS News in June.