At a time when the United States hopes to exert maximum pressure on Iran, a regional bloc created by Gulf Arab countries to counter Tehran looks increasingly more divided ahead of the anniversary of the diplomatic crisis in Qatar.

The sheer lack of cooperation by the six members of the Gulf Cooperation Council already has seen the US limit some military exercises and send Secretary of State Mike Pompeo to the region to urge allies to end the boycott of Qatar, a tiny, gas-rich nation.

The council consists of Bahrain, Kuwait, Oman, Qatar, Saudi Arabia and the United Arab Emirates. On June 5 last year, Bahrain, Saudi Arabia and the United Arab Emirates, along with Egypt, cut ties to Qatar, citing its close links with Iran and what they said was Qatar’s support for extremist groups in the region.

They launched the economic boycott, stopping Qatar Airways flights from using their airspace, closing off the country’s sole land border with Saudi Arabia and blocking its ships from using their ports.

Read: Qatar crisis creates ‘new’ Gulf with no winners

Amid the dispute, Qatar restored full diplomatic ties to Iran. And just like Iran after the US pulled out of the nuclear deal with Tehran, Qatar appears to have no interest in ceding any ground, having already decried the demands as an affront to its sovereignty.

Ahead of the anniversary, Qatar’s Government Communication Office began sending messages out with the hashtags “movingforward” and “Qatarstronger”.

That leaves the Gulf Cooperation Council adrift at a time of regional tension.

The GCC long has been viewed as a regional counterweight to Iran and crucial for the US military. Bahrain hosts the US Navy’s 5th Fleet. Kuwait is home to US Army Central. UAE military bases host American fighter jets, drones and soldiers, while Dubai’s Jebel Ali port is the Navy’s busiest foreign port of call. Qatar’s massive al-Udeid Air Base holds the forward headquarters of the US military’s Central Command.

While hosting no troops, Oman does allow US forces access to its bases and serves as a crucial go-between for US and Western diplomats and Iran. Saudi Arabia also relies on US military support for its ongoing war in Yemen against Shiite rebels there.

The Qatar dispute has seen a public reordering of the GCC.

Saudi Arabia and the neighboring UAE have taken on an increasingly neoconservative foreign policy, as seen in their military intervention in Yemen. Ties between Abu Dhabi’s powerful crown prince, 57-year-old Sheikh Mohammed bin Zayed Al Nahyan, and Saudi Arabia’s assertive 32-year-old Crown Prince Mohammed bin Salman have grown closer. Bahrain, long dependent on Saudi money to aid its troubled economy, cast its lot with the kingdom and the UAE.

Kuwait, ruled by 88-year-old Sheikh Sabah Al Ahmad Al Sabah, has sought to mediate the dispute. It hosted a GCC summit in December that it hoped would bring the bloc together. Instead, it only saw the UAE and Saudi Arabia upstage it by announcing its own closer union.

For Oman and its 77-year-old ruler, Sultan Qaboos bin Said, the country has sought to maintain its own separate diplomatic identity from the larger GCC. The sultanate’s ports also have become a crucial lifeline to Qatar.

Both Kuwait and Oman feel the pressure of the diplomatic dispute. The two countries have yet to prepare for the coming generational leadership shifts that await them. There is no clear successor to Sultan Qaboos, while an internal dispute among the branches of Kuwait’s ruling family remains likely.

The two also undoubtedly have seen the criticism by Saudi and Emirati media of Qatar’s ruling emir, 38-year-old Sheikh Tamim bin Hamad Al Thani, which has included promoting exiled Qataris as possible leaders for the country. Open criticism of ruling families is extremely rare among Gulf Arab nations, even during border disputes in the 1990s that saw some skirmishes.

Threats of military action also circled Qatar in the early days of the crisis. The troops and equipment of Saudi Arabia and the UAE dwarf those of Kuwait, Oman and Qatar’s armed forces.

Gulf Arab nations have relied on US military power as a safety net since President Jimmy Carter’s 1980 pledge to use force to defend its interests in the Persian Gulf. The aftermath of the 1991 Gulf War cemented that, as has America’s reliance on Gulf bases for its wars in Afghanistan and Iraq.

However, it remains unclear what options the US would have in a confrontation between Gulf Arab nations themselves, although one does not look imminent.

Gulf states also have grown increasingly wary of President Donald Trump. He initially came out in support of the nations boycotting Qatar, only later to back off.

Explore: Trump welcomes Qatari Emir in from the cold

Investigations into Trump also have touched the UAE and Qatar, while nations involved in the dispute have spent millions of dollars on Washington lobbyists and influence peddlers.

For now, the crisis has improved ties between Qatar and Iran. The Islamic Republic immediately opened its airspace to Qatar Airways after the boycotting nations blocked its routes, as well as sent food and other goods into the capital of Doha. In return, Qatar has restored full diplomatic relations with Iran, with which it shares a massive offshore natural gas field.