Dhaka, April 9 -- Saudi Arabia, with its wealth linked inextricably to oil revenue, faces mounting pressure to raise debt or cut spending after a plunge in crude prices, complicating plans to fund an ambitious agenda to diversify its economy.

Oil prices have tumbled to near four-year lows on fears a trade war will hit global growth and after a surprise decision by some OPEC+ oil producers, including Saudi Arabia, to boost their output plans.

The price decline threatens to erase tens of billions of dollars of Saudi revenue, along with a planned drop in dividends from state-controlled energy giant Saudi Aramco.

The International Monetary Fund and economists estimate Riyadh needs oil prices of over $90 a barrel to balance its budget. Benc...