Saudi Arabia, Bahrain and the United Arab Emirates withdrew their ambassadors from Qatar last Wednesday after accusing the emirate of meddling in their internal affairs.
Egypt followed suit the next day, formalising a breach of diplomatic ties that began shortly after the overthrow of President Mohammed Morsi.
The move has added to Qatar's isolation over its support for the Muslim Brotherhood and other allied Islamist groups in the region, who in recent months have seen the gains they made in the Arab Spring rolled back.
BBC correspondents around the region describe below how Qatar is now viewed
Mark Lobel, Dubai
For the best part of a year, Qatar's neighbours had banked on avoiding this escalation.
They had hoped the new Emir, Sheikh Tamim bin Hamad Al Thani, would offer a change from what they considered deeply unpopular policies in Libya, Syria, Egypt and Tunisia.
They had wanted a return to the days when the Arabian Peninsula's most powerful rulers worked together to resolve crises rather than exacerbate them.
The message received by Qatar's neighbours was that change was on its way. But, similar to when Mohammed Morsi ruled in Egypt, a perception grew of failure to fulfil promises.
Now those divisions are, unusually for the Gulf, laid bare in public.
The Emiratis and Saudis see members of the Muslim Brotherhood and other Islamists as "terrorists" threatening their ways of life, along with those of Bahrainis and Egyptians. The Qataris are accused of playing host to them and broadcasting anti-UAE sermons by one of their key figures.
People here are dumbfounded as to why Qatar has nailed its colours to the Brotherhood and other Islamist groups' masts in the first place.
Warning shots were fired when the UAE's foreign minister summoned the Qatari ambassador to Abu Dhabi and an alleged Brotherhood "cell" was put behind bars.
This high-profile joint action between Cairo, Riyadh, Manama and Abu Dhabi is the latest attempt to change Qatar's behaviour.
But if the withdrawal of ambassadors, broadcasters and columnists from Doha does not get the message across, these political differences could tear apart valuable and important economic and security ties between the neighbours.
No-one is seriously predicting that yet, but the government here remains tight-lipped about how far it thinks this row will go.
Rushdi Abu Alouf, Gaza City
It is no coincidence that the prime minister of the Hamas-led government in Gaza, Ismail Haniya, telephoned the emir of Qatar shortly after the withdrawal of the Gulf ambassadors from Doha last week.
After the fall of the Muslim Brotherhood government in Egypt in July, Hamas was left with no other allies in the region.
Hamas's relationships with Syria and Iran have been damaged by the decision of its political leader, Khaled Meshaal, to declare his support for the uprising against President Bashar al-Assad and to leave Damascus.
Hamas has had no choice but to seek to strengthen its alliance with Qatar.
Officials are under pressure and worried that the interim authorities in Egypt may try to kill two birds with one stone.
By stopping the transfer of building materials for Qatari-funded projects in Gaza through the Rafah border crossing, they could hurt both Hamas and Qatar.
The projects, worth $450m (£270m), were announced by the former Emir, Sheikh Hamad bin Khalifa Al Thani, while he visited Gaza in 2012.
Palestinians usually choose their friends or enemies according to which political party they support.
Supporters of Hamas believe that Qatar is a strategic ally, while the followers of Palestinian Authority President Mahmoud Abbas's Fatah party believe the emirate is deepening political divisions by actively supporting one group and ignoring the other.
Rana Jawad, Tripoli
The governments in Tripoli and Doha maintain a cordial relationship, but the relationship between Qatar and the Libyan street has withered almost as quickly as it blossomed during the 2011 uprising against Muammar Gaddafi.
Libyans do not take too kindly to foreign powers meddling in their internal affairs.
This reality has left Western countries and international organisations such as the UN tiptoeing around Libya and carefully considering the type of assistance they offer during what has been a very challenging and, at times, violent transition.
What has come across to many here as Qatar's more overt and aggressive interventionist policy has not helped.
Qatar's rise and fall in Libya is mainly linked to what many believe is its empowerment of the Muslim Brotherhood.
Libya's problems are deeply rooted in its competing regional, social and political groups. But the Brotherhood's political arm, the Justice and Construction Party, has been blamed for much of the political tension and insecurity in post-revolutionary Libya.
Trips to Qatar by senior Islamist figures have further fuelled suspicions.
In Benghazi, where anti-Gaddafi protesters once waved Qatar's flag alongside those of France and the UK, an effigy of Qatar's former emir was burnt to a crisp last year.
That sentiment has gradually spread across the country.
The ousting of President Morsi in Egypt last year appears to have given Libyans further cause to harden their stance against the Muslim Brotherhood and - by association - Qatar.
The emirate is also seen as having waged a proxy war on Libyan territory along with other Gulf Co-operation Council (GCC) states.
Observers here believe - rightly or wrongly - that some of the most powerful and competing militia brigades, along with their local political backers, are being bankrolled by Qatar, Saudi Arabia and the UAE.
Angy Ghannam, Cairo
Qatar has never been popular as far as the Egyptian government or people are concerned.
However, this changed in 2011, when the Qatar-based and funded TV network, al-Jazeera, openly sided with the protesters in Tahrir Square and provided them with the media outlet they needed to show what was happening across Egypt.
Many Egyptians tuned in to see what their local media were not showing them, and Qatar's reputation among Egyptians rose accordingly.
A year later, the Gulf state became the main ally of Mohammed Morsi and the Muslim Brotherhood.
Today, the situation has not only gone into reverse, but Qatar's status is now lower than during Hosni Mubarak's rule.
Since the military overthrew Mr Morsi in July, the Brotherhood's popularity among many Egyptians has fallen and seems to have taken Qatar with it.
The military-backed interim government is openly critical of Qatar and general feeling among Egyptians is that Qatar is an enemy working to destabilise the country.
Although al-Jazeera played a key role in enhancing Qatar's popularity after the 2011 uprising, it is now one of the main causes of the hostility directed towards the emirate.
For a while Qatar itself has not been outspoken in its public comments about the recent events in Egypt. Its sponsorship of a channel that is seen by millions of pro-army Egyptians as biased and provocative appears to have caused it a lot of damage.
Reading through Egyptian traditional and social media, one quickly gets a measure of the level of hostility towards Qatar. For many, Qatar now tops their lists of most-hated countries - more unpopular even than Israel.
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