BAGHDAD — Iraqi Airways resumed commercial flights between the central province of Najaf and Iranian airports on Monday, according to Iraq's state-run Iraqi News Agency, restoring air links suspended over concerns about U.S. secondary sanctions.

The suspension at Najaf and three other Iraqi airports had stemmed from fears that international contractors would face penalties for handling flights connected to Tehran. The resumption allows Iraq's flag carrier to restore operations halted when foreign service providers withdrew due to those concerns.

Abuzar Shiroudi, chief of Iran's Civil Aviation Organisation, told Iran's IRNA news agency that the International Civil Aviation Organization had ruled in Iran's favor on its protest over the U.S. aviation sanctions. He said Iran's Foreign Ministry is coordinating legal efforts to resume flights.

Iran filed a formal complaint with ICAO and also submitted a case to the International Court of Justice in The Hague addressing alleged attacks on airports, aircraft and radar systems. Any potential compensation depends on the court's final ruling.

U.S. sanctions against Iranian airlines took effect Sept. 23, subjecting foreign airports and companies providing services to sanctioned Iranian carriers to the risk of secondary penalties.

Iran is seeking explanations from several countries through diplomatic channels regarding halted flight routes, Shiroudi said.

Despite the restrictions, Iranian aviation has not been entirely grounded. The CEO of Tehran's Imam Khomeini International Airport told Iran's semi-official Fars news agency that flights to East Asia are operating without cancellations.

Airports in Azerbaijan, Georgia, Iraq, Oman and the United Arab Emirates had recently canceled flights operated by Iranian airlines before the Najaf resumption.