Big European banks remain reluctant to work in Iran four months after the lifting of international sanctions under a landmark nuclear deal with world powers, an Iranian official said Sunday.

"Major European banks have not yet started their interactions with Iranian banks, but some medium- and small-sized financial institutions have established relations, including opening letters of credit," deputy foreign minister Abbas Araghchi told state broadcaster IRIB.

He accused "extremist lobbies" in the United States, Israel and Saudi Arabia of stirring up animosity towards Iran to prevent it from reaping the benefits of the landmark nuclear deal signed last July.

When the agreement came into effect in January, Washington lifted sanctions directly related to Tehran's nuclear programme but it maintained others imposed over its ballistic missile programme and its alleged support of "terror" groups.

Several European banks have received massive fines in the United States in the past after being found guilty of violating US sanctions against Iran and all remain wary of incurring similar punishment.