Doha: Saudi Arabia, Egypt, Yemen, Bahrain and the United Arab Emirates (UAE) on Monday announced they were severing diplomatic ties with Qatar, and accused the Gulf state of supporting terror groups, including the Muslim Brotherhood.
The Saudi Press Agency (SPA) said Riyadh severed its diplomatic ties to "protect national security from the dangers of terrorism and extremism".
The Egyptian Foreign Ministry said that Qatar's policy "threatens Arab national security and sows the seeds of strife and division within Arab societies according to a deliberate plan aimed at the unity and interests of the Arab nation," Al Ahram news agency reported.
The five countries announced they would withdraw their diplomatic staff from Qatar, and also that they were closing their airspace and borders severing land, sea and air contact with Qatar within the next 24 hours.
The SPA quoted a Saudi official as saying that Qatari troops would be pulled from the ongoing war in Yemen due to Doha's "practices that strengthen terrorism" and its support to groups "including Al Qaeda and the Islamic State, as well as dealing with the rebel militias."
Bahrain said Qatar has interfered in its internal affairs, engaged in negative media coverage against it, and supported terrorist activities and armed groups, as well as financed Iranian-backed groups that are responsible of vandalism and violence in the country, reports Xinhua news agency.
The country has asked Qatari diplomats to leave within 48 hours.
The UAE has also accused Qatar of "supporting, funding and embracing terrorism, extremism and sectarian organisations", according to state news agency WAM.
The Yemen government also announced that it was severing all ties with Qatar, and accused it of working with its enemies in the Iran-aligned Houthi movement, state news agency Saba reported.
"Qatar's practices of dealing with the (Houthi) coup militas and supporting extremist groups became clear," the government said in a statement.
It added that Yemen supported the decision of a Saudi-led coalition, fighting for more than two years to oust the Houthis from the Yemeni capital Sanaa, to remove Qatar from its ranks.
In response, Qatar's Foreign Ministry said it regretted the measures by the Arab nations, and called the decisions "unjustified".
"The measures are unjustified and are based on claims and allegations that have no basis in fact," Al Jazeera TV cited the statement, adding the decisions would "not affect the normal lives of citizens and residents".
Meanwhile, US Secretary of State Rex Tillerson urged the Gulf nations to stay united.
"We certainly would encourage the parties to sit down together and address these differences," he was quoted by Al Jazeera as saying in Sydney.
"If there's any role that we can play in terms of helping them address those, we think it is important that the GCC (Gulf Cooperation Council) remain united."
Tillerson said despite the impasse, he did not expect it to have "any significant impact, if any impact at all, on the unified fight against terrorism in the region or globally".
Etihad Airways, the UAE's flag carrier, said it would suspend flights to and from Qatar beginning Tuesday morning.
It was not immediately clear how Monday's announcement would affect other airlines.
A Saudi-led coalition which for more than two years has been fighting Iran-backed rebels in Yemen separately announced that Qatar was no longer welcome in the alliance.
Monday's move comes after Qatar alleged that hackers last month took over the site of its state-run news agency and published what it called fake comments alleged to be from its ruling emir about Iran and Israel, Al Ahram reported.
Following the hacking, comments "falsely" attributed to Qatar's emir, Sheikh Tamim bin Hamad Al Thani, were broadcast in Qatar.
Qatar's government categorically denied that the comments, in which the country's leader expressed support for Iran, Hamas, Hezbollah and Israel while suggesting that US President Donald Trump may not last in power, were ever made.
In March 2014, Saudi Arabia, the UAE and Bahrain had recalled their ambassadors from Qatar for its alleged backing of then-Egyptian President Mohamed Morsi, a Muslim Brotherhood member.
However, eight months later they returned their ambassadors as Qatar forced some Brotherhood members to leave the country.