No time specified for press event. Scheduled for 7 pm CET.
If talks were breaking down, they wouldn't announce it in a press conference. This should be the announcement of a deal and it's bearish for oil.
Update: Immediate downside in oil.
Update 2: There's talk about an Al Jazeera report that says it's not a deal but saying that it's close and more negotiations are to come.
Update 3: But that Al Jazeera article might be old.
If a deal is announced, I suspect some traders who sold oil on the rumor will be buying it back on the result, especially with a long weekend coming.
Update 4: Reuters reports: Joint statement between Iran's Zarif and EU's Mogherini is being finalised, says western diplomat.
and AP reports: US-Iran agree on preliminary nuke deal but differ on how much can be disclosed.
Sounds like a done deal.
Update 5: Naturally, Congress is the sticking point.
Via AP: "Pressured by congressional critics in the U.S. who threaten to impose new sanctions on Iran over what they say is a bad emerging deal, the Obama administration is demanding significant public disclosure of agreements and understandings reached at the current round. But the officials say Iran wants a minimum made public."
Update 6: The press conference isn't for a couple hours. Almost everything will probably leak out before it starts but the details don't particularly matter at this point.