With the midnight deadline fast approaching, negotiators expect the talks to continue into Tuesday. Despite the delay, those involved in the talks remain optimistic that a deal is close.
"Iran deal is the victory of diplomacy & mutual respect over the outdated paradigm of exclusion & coercion. And this is a good beginning," Iranian President Hassan Rouhani said on Twitter.
"No deal on Monday, nuclear agreement possible on Tuesday," Press TV announced on Monday, citing Iranian Foreign Minister Mohammad Javad Zarif.
White House press secretary Josh Earnest also indicated that negotiators were "making genuine progress," according to the Associated Press.