Iran says some foreign companies have refused to refuel its planes at European airports as a result of international sanctions imposed on Tehran.
Foreign Ministry spokesman Ramin Mehmanparast said Tuesday that some Western companies have "unfortunately" adopted "inappropriate" measures. He said Iran is advising the governments of these companies against "acting beyond the regulations" or the United Nations Security Council sanctions, which he called "illegal."
Iran is under four sets of U.N. sanctions for its refusal to stop enriching uranium. Tehran says its nuclear program is for peaceful purposes.
The EU and several countries also have imposed their own penalties on Iran.
China is denying a report that officials are allowing some Chinese companies to help Iran develop nuclear weapons. Foreign Ministry spokesman Ma Zhaoxu told reporters Tuesday China is enforcing sanctions against Tehran, adding that China has fulfilled its international obligations.
Ma also said China has made its position clear to the United States.
Late Sunday, The Washington Post reported that U.S. officials are concerned China is letting some companies bypass the sanctions. The article quoted an unnamed official, who said the U.S. State Department has asked Chinese officials to investigate.
China is one of Iran's main trading partners.
Some information for this report was provided by AFP and Reuters.