Arab nations on Monday (June 5th) cut ties with Qatar, accusing it of supporting extremism in the biggest diplomatic crisis to hit the region in years.
Bahrain, the UAE, Yemen and the Maldives joined Saudi Arabia and Egypt in severing relations with Qatar, with Riyadh accusing Doha of supporting groups, including some backed by Iran, "that aim to destabilise the region".
The Saudi Press Agency (SPA) said Riyadh cut diplomatic ties and closed borders with its neighbour to "protect its national security from the dangers of terrorism and extremism".
The "decisive" measure was due to "gross violations committed by authorities in Qatar over the past years", the Saudi statement said.
The UAE followed suit, and Egypt's foreign ministry also accused Doha of supporting "terrorism" as it announced the severing of diplomatic relations and the closure of Egyptian ports and airports to Qatari vessels and planes.
Bahrain's news agency said the kingdom was cutting ties with Doha over its insistence on "shaking the security and stability of Bahrain and meddling in its affairs".
Qatar reacted with fury, denying any support for extremists and accusing its Gulf neighbours of seeking to put the country under "guardianship".
The crisis was likely to have wide-ranging consequences, not just for Qatar and its citizens but around the Middle East and world.
Weeks of rising tensions
Monday's announcement followed weeks of rising tensions between Doha and its neighbours, including Qatari accusations of a concerted media campaign against it and the alleged hacking of the Qatar News Agency.
The Gulf states and Egypt said they were severing diplomatic ties and closing transport links with Qatar, which relies on imports from its neighbours.
The Gulf states banned their citizens from travelling to Qatar and ordered Qatari citizens to leave within 14 days.
Saudi Arabia closed its borders with Qatar, and "all land, sea and aviation ports", effectively blocking food and other supplies exported by land to Qatar.
Local media in Qatar reported there was already some panic buying as people stock up on food.
The Qatar Stock Exchange tumbled 8% on opening and eventually closed down 7.58%.
Riyadh accused Doha of harbouring "terrorist and sectarian groups that aim to destabilise the region", including the "Islamic State of Iraq and Syria" (ISIS) and al-Qaeda.
The kingdom also accused Doha of supporting Iran-backed "terrorist activities" in Saudi Arabia's Eastern Province, as well as in Bahrain.
Qatar has consistently denied any support for extremists or Iran and did so again after Monday's move by its neighbours.
"The measures are unjustified and are based on false and baseless claims," the Qatari foreign ministry said, insisting authorities would "take all measures necessary... to foil attempts to affect or harm Qatar's society and economy".
Economic consequences were already emerging, with UAE carriers Emirates, Etihad, flydubai and Air Arabia, as well as Saudi Airlines, announcing the suspension of all flights to and from Qatar.
Qatar Airways -- one of the region's busiest airlines -- said it had suspended all flights to Saudi Arabia with immediate effect, at least until the end of Monday.
Abu Dhabi's Etihad and Dubai's Emirates airlines said flights would stop on Tuesday, after the UAE, Saudi Arabia and Bahrain said they would cut all air, land and sea links with Qatar within 24 hours.
Both carriers said the measure will stay in place "until further notice".
Saudi Airlines said it was suspending flights to Qatar with immediate effect.
Arab coalition expels Qatar
The Arab coalition battling the Iran-backed Houthis (Ansarallah) in Yemen said it had expelled Qatar from the group.
The coalition accused Qatar of providing "support to (terrorist) organisations in Yemen" -- the first time it has made such a claim.
Gulf countries previously recalled their ambassadors from Qatar in 2014, but Monday's moves go much further.
Turkey, which enjoys friendly relations with Qatar and other Gulf countries, offered its help, with Foreign Minister Mevlut Cavusoglu saying, "We will give any kind of support for the situation to be normalised."
Hints of an impending crisis emerged last month when Doha alleged that hackers were behind the release of false remarks attributed to Emir Sheikh Tamim bin Hamad Al-Thani published on the Qatar News Agency website.
Doha denied the comments and said it had been the victim of a "shameful cybercrime".
The crisis is the worst to hit Gulf Arab nations since the creation in 1981 of the Gulf Co-operation Council (GCC) grouping Saudi Arabia, Bahrain, the UAE, Kuwait, Oman and Qatar.
There was no immediate word from Kuwait and Oman on Monday on their ties with Qatar.
Last week, the Qatari emir travelled to Kuwait to meet Emir Sheikh Sabah al-Ahmad Al-Sabah in what was widely seen as an attempt at mediation by the Kuwaitis.