DAMASCUS, Syria — The Syrian government is buying up local currency and raising penalties for black market deals to try to stop the fall of the pound, which has tumbled to record lows against the U.S. dollar.

State news agency SANA said the government approved Wednesday a bill that criminalizes business deals in currencies other than the pound, with penalties ranging from 3 to 10 years imprisonment.

SANA also quoted Central Bank Governor Adib Mayyaleh as saying that the bank sold $50 million to foreign exchange companies Wednesday at the rate of 247.5 pounds to the dollar.

The pound was trading Thursday at 260 to the dollar, a day after the exchange rate fell to 310 pounds. The currency began a sharp descent last month after the U.S. decision to arm Syrian rebels.