President may take business delegation if nuclear deal clinched in first Tehran visit by western leader for years.
Ayatollah Ali Khamenei has broken his silence on the nuclear agreement.
"I neither support nor oppose the deal. Everything is in the details, it may be that the deceptive other side wants to restrict us in the details," Khamenei said in a speech broadcast live on state television.
The president tried to clarify his approach to Iran and Israel, but ended up muddying the water.
Convincing Congress to accept the Iran nuclear framework agreement will be a daunting political challenge for Obama.
Netanyahu has not yet publicly commented on the matter.
British foreign secretary warns "key issues" still to be resolved as talks on preliminary framework pass deadline.
The Congressional Black Caucus may decide whether Obama's critics nix a nuclear deal with Iran.
The "open letter" to Tehran may raise laughs here, but it will make the Mullahs less likely to come to an agreement.
U.S. to convince King Salman that diplomacy is solution for Iran nuclear programme after fears of Shi'ite proxies.