President Obama on Friday announced that he had spoken by phone with Iranian President Hassan Rouhani, marking the first time since 1979 that leaders from the two nations had held direct talks.

Speaking during a brief news conference in which he also urged House Republicans to not shut down the government, Obama said he and Rouhani had discussed Iran's nuclear ambitions, adding that resolving the issue would "serve as a major step forward in a new relationship between the United States and the Islamic Republic of Iran."

"A path to a meaningful agreement will be difficult," he added. "And at this point both sides have significant concerns that will have to be overcome. But I believe we’ve got a responsibility to pursue diplomacy and that we have a unique opportunity to make progress with the new leadership in Tehran.”

The news came on the same day that Iran and the U.N.'s nuclear agency held "constructive" talks about Iran's nuclear ambitions, part of a flurry of diplomatic activity that has sparked optimism that Iran is willing to make concessions on its controversial nuclear program.

In a sign of how far we've come since the last time leaders from the two nations talked, Rouhani confirmed the news on Twitter.