The U.S. Department of Transportation has fined Emirates $400,000 for operating flights under JetBlue Airways code in the airspace that the Federal Aviation Administration (FAA) has prohibited the U.S. operators from flying.

According to the report, Emirates operated flights carrying the B6 code for 19 days in July 2019 over parts of Iranian airspace with reportedly heightened military activities. The FAA had previously issued a ‘Notice to Airmen’ prohibiting all U.S. flights in the region.

Emirates had previously acquired economic licensing authority from the U.S. to display JetBlue’s (JBLU) designator code B6 on flights operated by the Emirates. However, the conditions for the agreement only apply as long the Gulf carrier conducts the flights under FAA’s permission.

According to the Emirates’ response highlighted in the statement, the airline has suspended all but one service of the Tehran Flight Information Region (OIIX) above the Persian Gulf and the Gulf of Oman out of ‘an abundance of caution’ after receiving FAA’s directive. But due to an ‘internal oversight’, the carrier has retained the B6 code by complete accident.

Once the Emirates became aware of the situation, the airline immediately ceased passengers’ transportation under the B6 code on flights through the OIIX region. At the same time, the Gulf carrier stated that it quickly implemented internal organizational and procedural changes to avoid any future issues regarding the matter.

Emirates said that “it takes its regulatory compliance responsibilities extremely seriously” and has “agreed to this settlement in the interest of resolving the matter.”

The carrier will have to pay $200,000 of its fine within 120 days of the issuance date, according to the report. The remainder will be renounced if the Emirates manage to avoid any violations for one year starting October 1, 2020.