The Iran nuclear talks, which had been scheduled to wrap up Tuesday, have been extended. The U.S. and the five other nations negotiating with Tehran over its nuclear program announced they'll meet for another week, as it became clear that they weren't likely to reach a deal by today's deadline.

Envoys from the U.S., Russia, France, China, Britain and Germany — known as the P5+1 in diplomat-speak — and from Iran agreed to extend an interim accord that gives relief from some economic sanctions in return for Tehran's agreement to freeze some nuclear activities.

President Obama, asked about the talks during a White House news conference, said if negotiators are not confident that the pathways for Iran's obtaining a nuclear weapons are closed, "then we're not going to get a deal."

"Ultimately this is going to be up to the Iranians," Obama said.

NPR's Peter Kenyon filed this report from Vienna, where negotiations were taking place:

"The interim accord requires Iran to sharply limit its stockpile of nuclear fuel, and gives U.N. inspectors daily access to certain facilities. A State Department official says all interim provisions will now remain in force for an additional week."During that time, negotiators will try to transform the broad framework agreed at Lausanne, Switzerland, in April into a legally binding, long-term agreement. Critics say the administration is relenting on too many of its earlier demands of Iran, but a U.S. official says the team knows exactly where its bottom line is and will either achieve that or not get a deal."Top Iranian officials joined the talks today, as did Russian Foreign Minister Sergei Lavrov."Copyright 2016 NPR. To see more, visit