A diplomatic standoff between Qatar and four other Arab nations that accuse it of sponsoring terrorism has turned a spotlight on an opaque network of charities and prominent figures freely operating in the tiny Gulf country.

It also raises questions about what constitutes a "terrorist" in the Middle East.

Saudi Arabia, the United Arab Emirates, Egypt and Bahrain have released a list of two dozen groups and nearly 60 individuals that they allege have been involved in financing terrorism and are linked to Qatar.

Qatar insists it condemns terrorism and that it does not support extremist groups.

The crisis began last month when the four Arab countries cut ties to Qatar. They demanded it end the alleged support of terrorism, and also that it cut its relations with Shiite power Iran and stop meddling in their affairs through support of Islamist opposition groups.

The energy rich nation is an important U.S. ally in a volatile region. It hosts about 10,000 U.S. troops at an air base used to launch coalition airstrikes against Islamic State fighters in Syria and Iraq.

The list of the groups and individuals released by Qatar's neighbors reflects longstanding concerns raised by U.S. officials. At the same time, it also includes political dissenters and opposition voices.

"The allegation that Qatar supports terrorism was clearly designed to generate anti-Qatar sentiment in the West," Qatari Foreign Minister Sheikh Mohammed bin Abdulrahman Al Thani said Wednesday in a speech in London.

As he spoke, foreign ministers from the Arab quartet met in Cairo to review Qatar's response to their demands. At the top of those demands is that Qatar end support for the Muslim Brotherhood, which briefly held power in Egypt and whose offshoots are active across the Middle East.

Though Qatar has cracked down on dissent at home, it views the Brotherhood as a legitimate political force. This has put it at odds with Saudi Arabia, the UAE and Egypt, which have branded the Brotherhood a terrorist organization and see it as a threat to political stability and security.

In his speech, Al Thani said there is a danger in "labeling political opponents as terrorists merely to silence them."

"Our neighbors see change - those advocating for it and those reporting on it - as a threat, and they are quick to label anyone who opposes their governments as a 'terrorist,'" he said.

The Brotherhood's spiritual guide, Sheikh Youssef al-Qaradawi, was among those accused by Qatar's neighbors of having ties with terrorism. The 90-year-old Egyptian cleric, who has lived in Qatar for decades, previously was embraced by Gulf leaders and was seen alongside Saudi Arabia's top cleric, Grand Mufti Sheikh Abdelaziz Al Sheikh, and the UAE's rulers.

In 2013, he joined a chorus of preachers in the Gulf urging young men to defend Sunni Muslims in Syria, calls that coincided with official backing of rebels fighting to oust Syrian President Bashar Assad.

Al-Qaradawi differed from other Gulf preachers in that he strongly criticized Egypt's government when it ousted the Brotherhood from power. He also was critical of Gulf countries that backed the lethal crackdown.

Qatar's support of the Brotherhood has made it an outlier, as has its unique role as a mediator in hostage negotiations, helping to free Western captives held by al-Qaida in Syria and Yemen.

Christopher Mellon, a researcher with the New America Foundation who co-authored a report about ransom payments, said these negotiations have often involved paying extremist groups. He said European governments have similarly gone to extreme lengths to keep these transactions private.

"They're very deliberately nontransparent. They don't want anyone to know that they've paid," he said.

Reports emerged earlier this year that Qatar paid hundreds of millions of dollars to release members of its ruling family who were kidnapped in Iraq. Allegations were raised that the complex deal included Qatari payments to an al-Qaida-linked group in Syria, as well as to an Iranian-backed militia in Iraq.

Qatar said reports of ransom payments to these groups are false and that it provided Iraq's government with financial aid to support the release of the Qataris.

The Arab quartet's list names a number of Qatari nationals, including Khalifa al-Subaie, Saad bin Saad al-Kabi, Abdelrahman al-Nuaymi, Abdel-Latif al-Kuwari and Ibrahim al-Bakr. All have been sanctioned by the U.S. Treasury Department as material supporters of al-Qaida. Four of the five appear to be living in Qatar - their assets are frozen, they are under surveillance and are barred from traveling abroad - but they are not imprisoned.

The U.S. Treasury said in the case of al-Bakr, he was detained in Qatar in the early 2000s for his role in a jihadist network but that he was released from prison after promising not to conduct terrorist activity in Qatar. Treasury alleged that in 2006, he played a key role in a terrorist cell plotting to attack U.S. military bases in Qatar, and as of mid-2012 was serving as a link between Gulf-based al-Qaida financiers and Afghanistan. He is apparently now residing outside Qatar, according to experts closely monitoring these cases.

While some of those sanctioned by the U.S. have faced trial and may have been detained by Qatar at some point, there does not appear to be a single individual jailed in Qatar for terrorism financing, according to David Weinberg, a senior fellow at the Foundation for Defense of Democracies.

Weinberg, who has written extensively about terror financing in the Gulf, said Qatar has been "inexcusably negligent" when it comes to cracking down on such financiers.

"There's been a longstanding debate within the U.S. government about whether Qatar's lax enforcement is related to lack of capability or lack of will. My research leads me to believe it's the latter: lack of will," he said.

The Associated Press asked Qatari officials on Wednesday for information on the prosecution of individuals suspected of terrorism financing. The officials said they would look into the request but had not provided details by Thursday evening.

Also on the list is Sheikh Abdullah bin Khalid Al Thani, a senior member of Qatar's royal family and a former interior minister. The quartet accused him of giving shelter to Khalid Sheikh Mohammed in the 1990s as he actively funded al-Qaida operations abroad, but before he became the alleged mastermind of the 9/11 attacks.

The allegations leveled against Qatar cut both ways.

In Britain this week, a right wing think tank released a study alleging Saudi Arabia has spent 67 billion pounds (nearly $87 billion) to export its austere Wahhabi interpretation of Islam around the world. The report by the Henry Jackson Foundation has increased pressure on the British government to make public a study on Saudi Arabia's role in inciting extremism in Britain.

The quartet list also names Kuwaiti national Hajjaj al-Ajmi, who is sanctioned by the U.S. for allegedly raising funds that led to the procurement of weapons for al-Qaida-linked fighters in Syria. The UAE and its allies say he raised some of that money through a Qatar-based fundraising campaign, but he appears to be living in Kuwait.