The Financial Times said oil major BP had stopped refuelling Iranian aircraft in response to far-reaching U.S sanctions to isolate Tehran economically, Reuters reported.
The new U.S. sanctions penalize companies supplying Iran with gasoline, but U.S officials have not made clear whether they believe the new law bars firms from refuelling Iranian airliners.
A spokesman for BP declined to comment on the Financial Times report, published on Monday on its website, or on individual contracts with airlines.
"We fully comply with any international sanctions imposed in countries where we operate. We also make sure that out JV partners are aware of sanctions as well," A BP spokesman said in a statement.
The Financial Times gave no source for its report.
Iran complained on Monday that its planes had been denied fuel in Germany, Britain and the United Arab Emirates.
Sources in the Middle East and Europe said that if flights were indeed denied fuel, it would be a decision by private firms attempting to comply with a new U.S. sanctions law, rather than any ban imposed by the countries where the planes landed. Governments said they were not aware of any ban on fueling.