CAIRO — In the tumultuous two years since President Abdel Fattah el-Sisi of Egypt came to power, one ally has kept the Arab world’s most populous country from economic ruin: Saudi Arabia pumped more than $25 billion into the faltering Egyptian economy, dwarfing aid from the United States.
The Saudis may have thought they were buying loyalty. But Egypt’s vote last month for a Russian United Nations resolution on Syria threatens to unravel Mr. Sisi’s relationship with Egypt’s most crucial benefactor.
Shortly after the vote, the Saudi ambassador to Egypt left Cairo for an unscheduled three-day visit to Riyadh. The state-owned Saudi oil company, Aramco, postponed a promised shipment of 700,000 tons of discounted oil in October, and the spokesman for Egypt’s oil ministry said the fate of November’s shipment remains unknown.
Then last week, the Saudi head of a major Islamic organization, who has since resigned, publicly mocked Mr. Sisi, exposing the rift in a new way.
Ahmed Moussa, a prominent Egyptian talk show host and staunch supporter of Mr. Sisi, was one of many Egyptian commentators who reacted angrily.
“They want to make Egypt kneel,” Mr. Moussa said of the Saudis, then offered his own threats. “Don’t you ever think you can pressure Egypt into backtracking,” he said. “Its decisions are sovereign. We don’t owe anyone anything. We are the ones who are owed.”
The fraying of the alliance between the two most influential Sunni nations is unfolding amid increasing sectarianism across the region. And the potential loss of Saudi support could hardly come at a worse moment for Egypt, whose economy is crashing amid a devaluing of its local currency, reduction in imports, and tourism tailspin.
Inflation in Egypt is at 14.6 percent, almost double the figure a year ago, and the government is awaiting approval of a $12 billion loan from the International Monetary Fund, which is likely to be conditioned on rolling back energy subsidies that could create political instability.
Saudi Arabia is itself grappling with the global decline in oil prices, and many of its longstanding political practices have been upended by Mohammed bin Salman, the deputy crown prince, who is defense minister and leads a powerful new council that oversees the state oil company.
Under Prince Mohammed, Saudi Arabia is going through a period of muscular nationalism and is trying to assert its weight as a Sunni regional power, particularly in trying to counterbalance Shiite Iran.
That has created a sense of wounded pride among Egyptians, who have long thought of their nation as the leader of the Arab world. They tend to be uncomfortable with their economic dependence on Saudi Arabia and sometimes dismiss the Saudis as oil-rich upstarts.