The Nigerian naira fell 0.24 percent against the dollar on Wednesday as demand for the U.S. currency strengthened despite the sale of large amounts of dollar by the local unit of Royal Dutch Shell, dealers said.

The naira closed at 164.58 to the dollar, weaker than Tuesday’s close of 164.18.

Shell sold an undisclosed amount of dollars to some lenders, but dealers said high demand countered its effect. Hard currency is in demand in Nigeria on concern that lower oil prices will weaken the naira and widen the current account of Africa’s biggest economy.

The naira firmed against the U.S. currency on Monday, after state-owned oil company Nigerian National Petroleum (NNPC), the source of most of the dollar liquidity traded on the interbank market, sold dollars to lenders.

But that has since dried up, dealers say.

“We hope the central bank will continue to intervene, otherwise the naira might depreciates further,” one dealer said.