Iran has criticized Greece and Italy for not buying its oil despite U.S. waivers, and said they had not offered Tehran any explanation.
"No European country is buying oil from Iran except Turkey," the semiofficial ISNA news agency quoted Oil Minister Bijan Zanganeh as saying on February 5.
Zanganeh added that Greece and Italy "don't buy Iranian oil and they don't answer our questions."
"We have called them many times, but they do not return our calls," the minister also said, according to the Fars news agency.
The United States granted the two EU member states and six other countries - Turkey, China, India, Japan, South Korea and Taiwan – temporary waivers to import Iranian oil when the U.S. reimposed sanctions on Iran's energy sector in November.
The waivers were aimed at giving these countries more time to comply with the sanctions.
Zanganeh said the U.S. sanctions on Iran were more difficult than the Iran-Iraq war in the 1980s, but insisted that Tehran would not allow Washington to reduce its oil exports to zero.
Oil exports are a key source of revenue for Iran.
Washington ramped up sanctions against the Iranian economy after President Donald Trump withdrew the United States from the 2015 nuclear deal between Iran and world powers last year.