The Iranian rial continued to weaken against the US dollar and other major currencies on January 31, with the sell rate for the greenback reaching IRR1,638,500 while the buy rate stood at IRR1,637,500, according to official exchange data.

The rial's fall comes as the USS Abraham Lincoln carrier strike group entered the Middle East on January 26, adding to market uncertainty as the prospect of a US military strike on Iran continues to weigh on the currency.

The euro traded at IRR1,942,500 on the sell side and IRR1,940,500 on the buy side, while the British pound was quoted at IRR2,243,500 sell and IRR2,241,500 buy.

The Swiss franc was at IRR2,120,500 sell and IRR2,118,500 buy, and the Canadian dollar traded at IRR1,202,500 and IRR1,201,500 respectively. The Australian dollar was quoted at IRR1,140,500 sell and IRR1,139,500 buy.

Among Asian currencies, the Singapore dollar traded at IRR1,290,000 sell and IRR1,289,000 buy, while the Hong Kong dollar was at IRR210,000 and IRR209,000. The Thai baht was quoted at IRR51,900 sell and IRR51,850 buy.

The Russian ruble was at IRR21,450 sell and IRR21,400 buy, and the Azerbaijani manat traded at IRR965,000 on both the sell and buy sides. The Swedish krona was quoted at IRR183,500 sell and IRR182,500 buy, and the Norwegian krone at IRR170,000 on both sides.

The rial has been under sustained pressure since mass protests erupted in late December over the collapse of the national currency and rising prices.

Daily trading volumes on Iran's commercial forex market rose 77% after the introduction of a unified exchange rate policy, with more than $710mn traded in the five business days ending on January 30, the Spokesman of Iran Exchange Centre said, Mehr reported on January 31.

Asghar Balsini said average daily trading volumes had reached $142mn since the single-rate policy came into effect, up from around $80mn before its introduction.

The highest single-day volume was recorded on January 27, when $201.1mn was traded. January 25 and January 28 followed with $156.6mn and $131.3mn respectively. Traders exchanged $100.7mn on January 26 and $121mn on January 27.

Balsini said the average dollar price during the week stood at IRR1,238,000 ($1), with a price fluctuation of 2.3%. The lowest recorded rate was IRR1,227,780 and the highest IRR1,256,230.

The spokesman attributed the sharp increase in forex supply to the unified rate policy and the return of export earnings to the market.