Doha (AFP) - US sanctions on Iran will not impact Qatar Airways' flights to the Islamic republic, the airline's boss Akbar al-Baker said on Monday.

Speaking at a high-profile business conference in the Qatari capital Doha, Baker said services to Iran would continue despite a tightening economic and political squeeze on Iran by Washington.

"Aviation is not a sanctioned industry, Qatar Airways will continue to operate into the cities we are currently operating in Iran," he said.

"Our flights to Iran will not be affected."

Qatar Airways' Iran destinations include Mashhad and Shiraz, while the airline operates daily flights to Tehran, according to its website.

Baker's comments come as US President Donald Trump's administration is expected to impose a second round of tough sanctions on Iran next month.

A first tranche of punitive measures were introduced in August by the US after it withdrew in May from the 2015 international deal aimed at curbing Tehran's nuclear ambitions.

Washington has also warned foreign businesses to steer clear of Iran.

Already, major European airlines including Air France and British Airways have stopped flights to Iran, following the sanctions' announcement.

Qatar is also under scrutiny over its relationship with Iran, with whom it shares the world's largest natural gas field.

Since June 5, 2017, Saudi Arabia, the United Arab Emirates, Bahrain and Egypt have imposed a sweeping embargo on Qatar, sparking the worst political rift to ever hit the Gulf, in part because of Iran.

The four countries accuse Doha of seeking closer ties with Tehran, Saudi Arabia's arch-rival, as well as supporting radical Islamist groups.

Qatar denies the charges, accusing its neighbours of seeking regime change.