The United States urged Egypt to not advance new business deals with Iran after the two countries agreed to allow direct flights for the first time in three decades, dpa reported.
"We continue to urge all countries - including Egypt - not to pursue any new business deals until Iran complies with its international obligations," said Mark Toner, a State Department spokesman.
Egypt and Iran reached a preliminary agreement on Sunday to resume direct flights between Cairo and Tehran, with 28 weekly flights. No timeframe was established for beginning the flights.
The United States and its Western allies have been trying to isolate Iran over its nuclear activities. The UN Security Council enacted sanctions in June, followed by similar moves from the US, European Union, and other countries.
Iran rejects accusations it is seeking atomic weapons, saying its nuclear work was purely peaceful.
Iran and Egypt have not had formal diplomatic relations since 1979.