Pakistan’s worst flooding in decades has tightened the supply of dollars, raising concerns that the rupee’s recent gains may not last, currency dealers and analysts said.

Exchange companies reported that many banks and outlets have suspended operations after being submerged, making dollars scarce across the country. “The supply of greenbacks has dried up as branches and banks are underwater,” said Saleem Amjad, chief executive of Link International Exchange Co., one of Pakistan’s largest foreign exchange firms, in comments to Bloomberg.

The disaster has killed more than 930 people and displaced over four million in the past two months. The economic fallout is extending beyond food and goods supply chains to foreign exchange, compounding pressure on a fragile economy.

The rupee has strengthened for 25 straight sessions, its longest rally in two years, according to central bank data. But analysts warned the shortage of dollars could disrupt imports and complicate the government’s case ahead of an International Monetary Fund loan review. Bloomberg economist Ankur Shukla cautioned that the floods could weaken already-thin reserves, which cover less than three months of imports.

The currency has risen 1.2% against the dollar since July’s low, supported by closer army oversight, an S&P Global Ratings upgrade, and a trade agreement with the United States. Still, dealers said some investors are holding on to dollars, expecting the rupee to weaken again.

Zafar Paracha, general secretary of the Exchange Companies Association of Pakistan, said the shortage was temporary and should ease within two weeks. However, a Topline Securities survey found that half of respondents still expect the rupee to fall to 285–290 per dollar by year-end.