As Sunni jihadists have pushed from Syria deep into Iraq, making startling gains now threatening Baghdad, they are highlighting the increasingly uncomfortable position of Persian Gulf states that have backed Syria's predominantly Sunni rebels.
Officially, Iraq's southern neighbors, Saudi Arabia and Kuwait, oppose groups such as the Islamic State in Iraq and Syria, or ISIS, which captured caches of advanced weaponry and forced a dramatic retreat of government security forces across northern Iraq last week.
But Saudi and Kuwaiti citizens have quietly funneled vast sums of money to and joined the ranks of ISIS and other jihadist groups fighting Bashar Assad's regime in Syria over the past two years, analysts and U.S. officials have said.
The Syrian conflict, which has pitted Sunni fighters against Syrian forces and Shiite militias backed by Iran, has now more tangibly than ever spilled across regional borders, setting off the most serious crisis in Iraq since the bloodiest periods of the U.S. occupation. As a result, the gulf-sponsored jihadists -- who could threaten the very integrity of the Saudi and Kuwaiti governments -- are suddenly on the gulf's back doorstep.
"While Sunni governments don't support ISIS," their people do, said Andrew Tabler, an expert on Arab politics at the Washington Institute for Near East policy. "The funding for ISIS, Jabhat al-Nusra and other jihadist organizations is coming from" gulf states. Now, those gulf states "are in an awkward position," he said.
And yet gulf governments are hardly expected to come to Iraq's aid. They have long harbored animosity toward Iraqi Prime Minister Nouri al-Maliki, a Shiite who came to power during the Iraq war and empowered the country's Shiite majority at the Sunnis' expense, and whom many Sunni Arabs view as a pawn of Iran.
Although Saudi Arabia and its gulf allies may fear ISIS, "they have no particular interest in shoring up Maliki's government," said Shadi Hamid, a Middle East expert at Washington's Brookings Institution.
Saudi King Abdullah bin Abdul Aziz has repeatedly refused to meet with Mr. Maliki, despite a long, shared border. "The king has a personal attitude that this man is a puppet in the hand of the Iranians, and he dismissed him from his book a long time ago," said Mustafa Alani, director of the National Security and Terrorism Studies Department at the Gulf Research Center.
Some -- perhaps many-- gulf citizens may even be cheering about the jihadists' rise, believing them to be a positive force against Iran and its proxies in a divided Middle East, he said. "This feeling is there," Mr. Alani said, that ISIS may have "taught the Maliki government a lesson."
Saudi Arabia remained silent at the weekend on the expanding Iraq crisis, even as the United States pledged to send assistance to Mr. Maliki's government.