Emirates planes are seen at Dubai International Airport, in Dubai, United Arab Emirates, Feb. 15, 2019. Photo: Reuters / Christopher Pike.

The US Transportation Department said Thursday it fined the airline Emirates $400,000 for operating flights in parts of prohibited Iranian airspace in 2019.

The flight was carrying the JetBlue Airways code and therefore subject to US regulations. The department said for 19 days in July 2019, Emirates operated flights over parts of Iranian airspace, even though the US Federal Aviation Administration had barred flights because of heightened military activities and increased political tensions.

Emirates told the department the issue was a result of an “inadvertent oversight” but “agreed to this settlement in the interest of resolving this matter.”

Emirates must pay $200,000 of the fine within 120 days. The remainder will be waived if it has no further violations within one year.

Emirates told the department it had suspended all flight operations in the designated Iranian airspace except twice-daily service to Tehran “for a limited time period, at a significant cost to Emirates.”

Emirates noted in a statement that the flight restrictions apply only on flights where it “transported passengers ticketed under a US air carrier’s designator code.”

The airline added it “takes its regulatory compliance responsibilities extremely seriously.”