The accumulation of $250 billion in bad debt threatens to drag developing countries into a historical series of defaults, Bloomberg Economics said, warning that Egypt, Tunisia, Pakistan and El Salvador are the most vulnerable.

Senior experts voiced their concerns, including former directors at Elliott Management, Jay Newman, and the World Bank’s chief economist Carmen Reinhart. Moody’s warned that Egypt, Tunisia and Ghana would be vulnerable to higher borrowing costs.

The bond credit rating company explained that African governments have relatively low foreign reserves available to cover bond payments due through 2026. This could turn into a problem, added if these countries are unable to roll over their bonds. Ghana is seeking $1.5 billion from the International Monetary Fund, while Egypt is seeking $12 billion.

Bloomberg Economics said that the countries under the most significant pressure tend to be smaller countries with a track record in international capital markets, with widespread concern about future challenges. With the Ukraine war continuing to pressure commodity prices, interest rates rising and the dollar asserting its strength, the burden on some countries is likely to be unbearable.