The continuing slump in global oil prices is punching holes in the budgets of oil-producing countries, including some OPEC members such as Iraq and Libya that are struggling with severe political and security problems.

Many members of the Organization of the Petroleum Exporting Countries need oil prices to average way above the current Brent crude oil price of $90 a barrel to balance their books. They have ratcheted up annual spending since the Arab Spring in 2011—and rely heavily on oil-export receipts for income.

But most Gulf monarchies with relatively small populations, such as OPEC’s biggest producer, Saudi Arabia, can cope with lower oil prices for some time, making it less urgent for them to cut output to boost prices.

Saudi Arabia said Friday it had increased crude output by 107,000 barrels a day in September to 9.7 million barrels daily. OPEC in total increased output last month to its highest level in more than a year.

That means the current price war within OPEC is set to continue, putting further pressure on weaker nations.