Saudi Arabia, the United Arab Emirates (UAE) and several other Sunni-majority countries have severed relations with Qatar since June 5, accusing the Gulf state of supporting terrorism based on its ties with the Muslim Brotherhood, Hamas and the Taliban. Another point of departure is Qatar's ties with Iran, with whom it shares one of the world's biggest gas fields.
Qatar has denied the accusations and called the collective decision "unjustified." Kuwait, Turkey and the US have all urged a political solution as the bloc isolates Qatar using various ad hoc sanctions, including shutting down their airspace to Qataris and blocking import routes.
The dispute began in May when Qatar's Emir Sheikh Tamim bin Hamad al Thani was reported to have made statements on the state news agency supporting Iran. Doha said the statements were fabricated and disseminated via a hack.
Here are the latest developments in the crisis:
June 26, Monday
Key US Republican threatens to block arms to Gulf
A top Republican lawmaker threatened to block US arms sales to members of the six-nation Gulf Cooperation Council including Saudi Arabia until their escalating rift with Qatar is resolved.
"All countries in the region need to do more to combat terrorism, but recent disputes among the GCC countries only serve to hurt efforts to fight ISIS [Daesh] and counter Iran," Bob Corker, chairman of the Senate Foreign Relations Committee, said in a letter to Secretary of State Rex Tillerson.
"For these reasons, before we provide any further clearances during the informal review period on sales of lethal military equipment to the GCC states, we need a better understanding of the path to resolve the current dispute and reunify the GCC."
Germany says Saudi demands "very provocative"
A list of 13 demands submitted by four Arab states to Qatar as a condition to lift their boycott on the Gulf country is "very provocative" because some items challenge Doha's sovereignty, German Foreign Minister Sigmar Gabriel said on Monday.
Gabriel said it would be tough for Qatar to accept all 13 items on the list and added that efforts were under way to define which conditions Qatar could accept, and which it viewed as problematic.
Iran urges Europe to help promote dialogue in Gulf
Iranian Foreign Minister Mohammad Javad Zarif called for Europe to use its influence to defuse tensions in the Gulf.
Speaking in Berlin, Zarif said the countries who blamed Iran or Qatar for terrorism were trying to avoid taking responsibility for their own failures in addressing the demands of their own people.
"One day it's Iran, today it's Qatar," he said. "It's an attempt to evade responsibility, escape accountability for this very fundamental ... failure of the state system to address, to respond to the demands of its populous."
Bahrain accuses Qatar of military escalation in Gulf row
Bahrain's foreign minister accused Qatar of creating a military escalation in a dispute with regional powers, in an apparent reference to Doha's decision to let more Turkish troops enter its territory.
Turkey, the most powerful regional player to stand with Qatar, has increased the number of its troops in the base since the crisis erupted.
"The foundation of the dispute with Qatar is diplomatic and security-oriented, never military," Bahrain's foreign minister, Sheikh Khalid bin Ahmed al Khalifa, said in a message on Twitter.
"Bringing in foreign armies and their armoured vehicles is the military escalation that Qatar has created," he added.
June 25, Sunday
Iran's Rouhani backs Qatar, rejects "siege"
Iranian President Hassan Rouhani voiced support for Qatar in its confrontation with Iran's rival Saudi Arabia and its allies, saying a "siege of Qatar is unacceptable," the state news agency IRNA reported.
"Tehran stands with the Qatari nation and government ... We believe that if there is a conflict between regional countries, pressure, threats or sanctions are not the right way to resolve differences," IRNA quoted Rouhani as telling Qatar's emir, Sheikh Tamim bin Hamad al Thani, in a telephone call.
"The siege of Qatar is unacceptable to us ... The airspace, land and sea of our country will always be open to Qatar as a brotherly and neighbouring country," Rouhani said.
For more on previous developments click here.