Oil-rich Saudi Arabia and the United Arab Emirates have just written another check to bail out their latest troubled ally.

The Gulf nations on Sunday pledged $3 billion to Sudan after longtime President Omar al-Bashir was toppled this month. In a statement, they said they'll deposit $500 million in Sudan's central bank to ease pressure on the currency. The remainder will go toward food, medicine and fuel.

It's the latest in a string of pledges as the two nations seek to maintain their political influence and prop up allies in the Middle East and beyond, even as lower oil prices weigh on their own economies. Over the past two years, they've promised aid to countries including Bahrain, Jordan, Yemen and Pakistan.