Lausanne, Switzerland — After more than a decade of on-again, off-again debate about Iran’s nuclear future and six intense days of negotiations in this tony lakeside resort, officials from the world’s most powerful nations on Tuesday set aside a self-imposed midnight deadline and agreed to talk some more.

State Department spokeswoman Marie Harf made the announcement eight hours before the deadline would have passed, noting in an email to reporters, “We’ve made enough progress in the last days to merit staying until Wednesday. There are several difficult issues still remaining.”

But the extension had been rumored throughout the day, with German news media saying diplomats had discussed stopping the clock, while White House press secretary Josh Earnest called the talks “constructive” and “productive.” “If we are making progress toward the finish line, then we should keep going,” he said.

The Tuesday deadline never was an actual deadline. It was the day picked for reaching what was called a framework agreement, so that details could be worked out before the official deadline, June 30, when a previous agreement that limited Iran’s nuclear program and eased international sanctions is to expire.

Given that the stakes for the final deal are considered everything from essential to Iran to existential for Israel, there was more than enough support for staying at the table if a couple more issues could be ironed out.

Iran is said to be holding out for quickly lifting the sanctions in return for agreeing to limits on its ability to enrich uranium, the key industrial process that leads to nuclear fuel for generating electricity and to the key ingredients for a nuclear weapon.

“Iran does not want a nuclear deal just for the sake of having a deal, and a final deal should guarantee the Iranian nation’s nuclear rights,” Iranian negotiator Hamid Baidinejad said Tuesday in Lausanne.

But there was no official statement of the sticking points or on the points of agreement. The negotiators — the United States, Great Britain, France, Russia, China and Germany on one side, Iran on the other — made no public appearances as the deadline approached.

To meet the needs of all parties, the final agreement would have to protect the Middle East and the world from Iran developing a nuclear weapon but allow Iran to continue to produce nuclear power and to process nuclear materials.

In return for agreeing to at least 10 years of restrictions on its program, Iran is insisting that U.S. and European economic sanctions be removed soon after there’s a deal in place. The other nations want to gradually ease the sanctions and leave the so-called “sanctions architecture” in place so that the sanctions can be “snapped back” into place if Iran strays from the agreement.

That, however, runs counter to wishes of many, including some Republicans in Congress and Israeli Prime Minister Benjamin Netanyahu, who warn that any deal that allows Iran to enrich uranium carries with it the risk that Iran will be able to develop a nuclear weapon in less time than the world could respond to stop it.

“The greatest threat to our security and to our future was and remains Iran’s effort to arm itself with nuclear weapons,” Netanyahu told the Israeli parliament Tuesday. “The agreement being formulated in Lausanne paves the way to this outcome.”

Because of such fears, one of the major negotiating points is the creation of what’s called a “one-year breakout” period for Iran, meaning controls on its nuclear program that would require at least one year after leaving the deal for the country to make a bomb.

Phil Coyle, a former associate director for national security and international affairs of the White House Office of Science and Technology and a former chief Pentagon technology tester, noted that he wasn’t sure the threat was so much practical or scientific as political.

“They’ve had years without close inspections, when they were enriching uranium, when they probably could have figured out a way to build a bomb in secret,” he said. “But the necessity depends on your view of Iran. Many in Congress see them as a serious threat. Others note that they’ve had time to build the weapons we fear, and haven’t, and think they might be telling the truth when they say they don’t intend to build nuclear weapons.”

In Germany, the newspaper Die Zeit noted: “Whatever a deal may look like, it will most likely not prevent Iran from obtaining nuclear weapons. This development can apparently at best be slowed down but not prevented. That is why technical detail like the number of centrifuges the country is allowed to operate is so important.”

Another newspaper, Generalanzeiger of Bonn, said the stakes were extremely high for President Barack Obama.

“These hours will tell whether Barack Obama deserved the Nobel Peace Prize after all,” the paper said. “Should the U.S. president achieve an agreement that verifiably and permanently guides Iran’s nuclear program into exclusively civilian channels, protecting Israel, the region and the entire world, it would mean that one of the most treacherous trouble spots is under control for now.”

Earnest said Obama was following the talks closely and knows that a bad deal is worse than no deal.

“If they are unwilling to make those serious decisions,” Earnest said of Iran, “I have no doubt that the president will be ready to move on to consider other alternatives. But we do continue to believe that the best way for the United States and for the international community to prevent Iran from obtaining a nuclear weapon is through diplomacy. And that’s why we are so aggressively pursuing this option.”