Saudi Arabia, Egypt, the United Arab Emirates and Bahrain severed their ties with Qatar on Monday, accusing it of supporting terrorism, opening up the worst rift in years among some of the most powerful states in the Arab world.

The coordinated move dramatically escalates a dispute over Qatar's support of the Muslim Brotherhood, the world's oldest Islamist movement, and adds accusations that Doha even backs the agenda of regional arch-rival Iran.

Announcing the closure of transport ties with Qatar, the three Gulf states gave Qatari visitors and residents two weeks to leave their countries. Qatar was also expelled from a Saudi-led coalition fighting in Yemen.

Economic disturbances loomed immediately, as Abu Dhabi's state-owned Etihad Airways said it would suspend all flights to and from Doha from Tuesday morning until further notice.

Oil giant Saudi Arabia accused Qatar of backing militant groups and broadcasting their ideology, in an apparent reference to Qatar's influential state-owned satellite channel al Jazeera.

"(Qatar) embraces multiple terrorist and sectarian groups aimed at disturbing stability in the region, including the Muslim Brotherhood, ISIS (Islamic State) and al-Qaeda, and promotes the message and schemes of these groups through their media constantly," the Saudi state news agency SPA said.

The statement accused Qatar of supporting what it described as Iranian-backed militants in its restive and largely Shi'ite Muslim-populated Eastern region of Qatif and in Bahrain.

Qatar had no immediate reaction to the announcements, and Qatari officials could not be reached for comment, but it has denied supporting terrorism or Iran in the past.

WORLD CUP, U.S. BASE

The measures are more severe than during a previous eight-month rift in 2014, when Saudi Arabia, Bahrain and the UAE withdrew their ambassadors from Doha, again alleging Qatari support for militant groups. At that time, travel links were maintained and Qataris were not expelled.

A split between Doha and its closest allies can have repercussions around the Middle East, where Gulf states have used their financial and political power to influence events in Libya, Egypt, Syria, Iraq and Yemen.

The diplomatic broadside threatens the international prestige of Qatar, which hosts a large U.S. military base and is set to host the 2022 World Cup. It has for years presented itself as a mediator and power broker for the region's many disputes.

Kristian Ulrichsen, a Gulf expert at the U.S-based Baker Institute, said if Qatar's land borders and air space were closed for any length of time "it would wreak havoc on the timeline and delivery" of the World Cup.

U.S. Secretary of State Rex Tillerson told reporters in Sydney on Monday that the spat would not effect the fight against Islamist militants and that Washington has encouraged its Gulf allies to resolve their differences.

The announcements come 10 days after President Donald Trump visited Riyadh to call on Muslim countries to stand united against Islamists extremists, and singling out Iran as a key source of funding and support for militant groups.

"It seems that the Saudis and Emiratis feel emboldened by the alignment of their regional interests - toward Iran and Islamism - with the Trump administration," said Kristian Ulrichsen, a Gulf expert at the U.S-based Baker Institute.

"(They) have decided to deal with Qatar's alternative approach on the assumption that they will have the (Trump) administration's backing."

India's Petronet:

India's Petronet LNG said on Monday it did not expect any impact on gas supplies from Qatar after Saudi Arabia, Egypt, the United Arab Emirates and Bahrain severed ties with the Gulf Arab state accusing it of supporting terrorism.

"I don't think there will be any impact on it. We get gas directly from Qatar by sea," R.K. Garg, head of finance at Petronet, told Reuters when asked to comment on the coordinated move to cut relations.Petronet LNG, India's biggest gas importer, buys 8.5 million tonnes a year of liquefied natural gas (LNG) from Qatar under a long-term contract. It also buys additional volumes from Qatar under spot deals.

Iran:

A senior Iranian official said on Monday the decision by some Gulf Arab states and Egypt to sever diplomatic ties with Qatar would not help end the crisis in the Middle East.

"The era of cutting diplomatic ties and closing borders is over... it is not a way to resolve crisis. These countries have no other option but to start regional dialogue," Hamid Aboutalebi, deputy chief of staff of Iran's President Hassan Rouhani, tweeted on Monday.

"What is happening is the preliminary result of the sword dance," he said in an apparent reference to U.S. President Donald Trump's recent visit to Saudi Arabia.

Oil, Economy and London Attacks:

Oil jumped after Saudi Arabia, Egypt, the United Arab Emirates and Bahrain cut ties with Qatar on Monday while sterling slipped after the weekend attacks in London that killed at least seven people and wounded 48, just days before Britain's general national election. 

Qatar is the biggest supplier of liquefied natural gas (LNG) and a major seller of condensate - a low-density liquid fuel and refining product derived from natural gas.

Global benchmark Brent> LCOc1 advanced 1.1 percent to $50.48 a barrel. U.S. oil CLc1 also climbed 1 percent to $48.17.

Dubai's stock index .DFMGI dropped 0.6 percent in early trade.

Sterling GBP=D3 fell as much as 0.3 percent before paring the losses to trade down 0.2 percent at $1.2868 on Monday. Attackers rammed a van into pedestrians on London Bridge on Saturday and then stabbed revelers in nearby bars.

But British stocks .FTSE are unlikely to see much adverse impact from the third terrorist attack in the country in as many months, with financial spreadbetter CMC Markets expecting the FTSE 100 .FTSE, which touched a record high on Friday, to open slightly higher.

Prime Minister Theresa May said Thursday's election would go ahead as planned.

'ARAB SPRING'

Qatar has used its media and political clout to support long-repressed Islamists during the 2011 pro-democracy "Arab Spring" uprisings in several Arab countries.

Muslim Brotherhood parties allied to Doha are now mostly on the backfoot in the region, especially after a 2013 military takeover in Egypt ousted the elected Islamist president.

The former army chief and now president, Abdel Fattah al-Sisi, along with the new government's allies in Saudi Arabia and the UAE, blacklist the Brotherhood as a terrorist organization.

Egypt, the Arab world's most populous nation, said on its state news agency 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."

Oil prices rose after the moves against Qatar, which is the biggest supplier of liquefied natural gas (LNG) and a major seller of condensate - a low-density liquid fuel and refining product derived from natural gas.

AL JAZEERA

In a statement on state news agency SPA, oil giant Saudi Arabia accused Qatar of backing militant groups and spreading their violent ideology, in an apparent reference to Qatar's influential state-owned satellite channel al Jazeera.

"(Qatar) embraces multiple terrorist and sectarian groups aimed at disturbing stability in the region, including the Muslim Brotherhood, ISIS (Islamic State) and al-Qaeda, and promotes the message and schemes of these groups through their media constantly," SPA said.

The statement went on to accuse Qatar of supporting what it described as Iranian-backed militants in its restive and largely Shi'ite Muslim-populated Eastern region of Qatif and in Bahrain.

There was no immediate Qatari reaction to the announcements, and Qatari officials could not be reached for comment, but it has denied supporting terrorism or Iran in the past.

Egypt, the Arab world's most populous nation, said on its state news agency 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."

Etihad and FlyDubai suspended

The Abu Dhabi-based airline Etihad says it is suspending flights to Qatar amid a growing diplomatic rift.

Etihad said on its website Monday its last flights “until further notice” would leave early Tuesday morning.

Etihad gave no reason for the decision. It is the flag carrier of the United Arab Emirates.

Dubai-based budget carrier flydubai said on Monday it would suspend flights to and from Doha from Tuesday after the United Arab Emirates severed ties with Qatar.

"From Tuesday 06 June 2017 all flydubai flights between Dubai and Doha will be suspended," the statement on Monday said.

In Sydney, U.S. Secretary of State Rex Tillerson said he didn’t believe the diplomatic crisis would affect the war against the Islamic State group in Iraq and Syria.

“I think what we’re witnessing is a growing list of disbelief in the countries for some time, and they’ve bubbled up to take action in order to have those differences addressed,” Tillerson said. “We certainly would encourage the parties to sit down together and address these differences.”

The decision comes after Qatar alleged in late May that hackers took over the site of its state-run news agency and published what it called fake comments from its ruling emir about Iran and Israel. Its Gulf Arab neighbors responded with anger, blocking Qatari-based media, including the Doha-based satellite news network Al-Jazeera.

Qatar long has faced criticism from its Arab neighbors over its support of Islamists. The chief worry among them is the Muslim Brotherhood, a Sunni Islamist political group outlawed by both Saudi Arabia and the UAE as it challenges the nations’ hereditary rule.