Qatar has made itself an invaluable ally for a number of countries around the world through its supply of natural gas, and also strategically allied itself with Turkey, whose government has coordinated with Doha on support for Muslim Brotherhood groups across the region and rebels in Syria. Fitch Ratings puts Qatar at AA.
A top Emirati diplomat has told The Associated Press that the United Arab Emirates was not behind the alleged hack that targeted the state-run Qatar News Agency.
He later told France 24 television that any further steps could take the form of "a sort of embargo on Qatar".
Describing the emir of Kuwait as "one of the wise men of the Gulf", Gargash said at this point he does not "see the conditions" right for mediation.
Tensions continue to escalate in the Middle East. Saudi Arabia and Qatar are both key USA allies in the region, both hosting massive US air bases necessary for the fight against ISIS, but Saudis are not thrilled with Qatar sharing the North Field with its rival Iran. Riyadh denied any involvement.
"This is a foreign policy gone wild", state minister for foreign affairs Anwar Gargash told AFP.
CNN and The Guardian have also reported that the Federal Bureau of Investigation believes Russian hackers planted a false story about the emir of Qatar in recent weeks, potentially contributing to the crisis.
Foreign Minister Sheikh Mohammed bin Abdulrahman al-Thani spoke as would-be mediators ranging from US President Donald Trump to Kuwait's ruling emir struggled to ease a crisis that Qataris say has led to a blockade of their nation.
But efforts to defuse the worst crisis among Gulf Arabs for two decades showed no immediate progress.
Sudan, which has close political and economic ties to Qatar, has expressed concern over "the regretful development between brotherly Arab states". Qatar strongly denies supporting terrorism, and on Tuesday called for talks to settle the dispute. Turkish exporters have also pledged to provide food and water to Qatar if needed.
Turkish defense industry giant BMC also has a Qatari partnership, and Qatari Emir Sheik Temim bought the most expensive part of the Bosphorus in 2015.
A company source later said the network was combatting a large-scale cyber attack but remained operational, and Qatar's official state TV said it had shut down its website temporarily after facing hacking attempts.
Sheikh Mohammed said Qatar could nonetheless survive "forever", adding that it respected global agreements and would continue supplying liquefied natural gas to the UAE.
"The measures are unjustified and are based on claims and allegations that have no basis in fact", Al-Jazeera quoted the Qatar Foreign Ministry, as saying, in a statement.
The UAE's state-owned Etihad Airways said all travelers holding Qatari passports were prohibited from traveling to or transiting through the emirates on government instructions.