As I type this post it is about 7pm Sunday in Sao Paulo, shortly after 2am Monday in Tehran.
I just spoke on the phone with a source within Brazil's diplomatic delegation currently in Iran who tells me that after 18 hours of negotiations the Brazilians are "very optimistic" and that talks on Sunday went "very well" on a negotiated solution to the Iran nuclear standoff.
The Brazilian member of the diplomatic corps said there was hope that an agreement could be announced as early as Monday morning.
Brazil's foreign minister, Celso Amorim, who is spearheading Brazil's negotiating team, apparently returned to his Tehran hotel room shortly after 11pm.
The news from the Brazilians seems to back up a late Reuters report on Sunday night in which Turkey Foreign Minister Ahmet Davutoglu was asked by a reporter whether there would be an agreement and he allegedly said: "Yes, it has been reached after almost 18 hours of negotiations."