The Iranian rial plunged to a record low against the US dollar on Tuesday, underscoring the mounting economic pressure on Tehran as Washington tightens sanctions and restricts the country's oil exports.

What happened: The rial was trading at more than 2.54 million to the dollar in Tehran's open market on Tuesday, down from around 2.4 million on Monday, according to Pashizi, a website tracking Iran's free foreign exchange market.

Tuesday's record low came just 27 days after the rial hit a previous record low of 2.2 million per dollar on Sept. 2. The rial has repeatedly weakened since the US and Israel began striking Iran on Feb. 28, while the Iranian economy was already suffering from sanctions, high inflation and weak growth.

Washington has intensified that pressure in recent weeks. On Aug. 24, the US Treasury launched “Operation Economic Outcast,” targeting Iran's financial networks and expanding the risk of secondary sanctions for foreign companies and banks that continue doing business with Tehran.