The White House on Monday declined to say whether a lifting of the conventional weapons embargo against Iran is now on the negotiating table in the Iran nuclear talks, which are continuing into Tuesday after blowing through multiple deadlines.

Press reports from Austria said the talks are hung up over whether the deal should also result in a lifting of the United Nations' conventional arms embargo against Iran. But when asked, presidential press secretary Josh Earnest said Monday that he couldn't "get into the details" of the final sticking points in the talks.

He did stressed that the U.S. is trying to focus the negotiations on sanctions relief related to Iran's nuclear program, not any lifting of restrictions on a conventional arms embargo.

"We've been very clear that the sanctions relief that Iran would be entitled to … would be those sanctions that have applied to Iran's nuclear program and possible weaponization of their nuclear program," he said. "That's the essence of this whole negotiation."

But Earnest never said explicitly that the arms embargo can't be part of the final deal.

Iran, with Russia's support, is reportedly pressing U.S. and other western negotiators to expand any nuclear deal to include the lifting of an embargo against the sale of conventional weapons and missiles. So far, the U.S. has vigorously resisted it.

"Under no circumstances should we relieve pressure on Iran relative to ballistic missile capabilities and arms trafficking," Gen. Martin Dempsey, chairman of the Joint Chiefs, testified in a hearing on Capitol Hill last week.

Asked whether Dempsey's comments reflect the administration's position, Earnest said: "You can certainly rely on Chairman Dempsey's" point of view.

The negotiations stalled Monday after both sides expressed optimism Sunday that a deal could occur within the next 24 hours.

Clearly, both sides are close and a deal could come quickly. Iranian President Hassan Rouhani suggested the two sides were nearly done in an errant tweet that he immediately deleted.

Rouhani earlier Monday tweeted: "#IranDeal is the victory of diplomacy & mutual respect over the outdated paradigm of exclusion & coercion. And this is a good beginning." Rouhani's account later re-posted the tweet, although it started by saying, "If #IranDeal,..."

Over the last four to six days, Earnest said, there has been "important progress" made but there are still "some pretty tough obstacles."

Pressed again on whether a convention arms embargo is now under consideration in the talks, Earnest demurred.

"I think at this point, this is the kind of conversation that if we reach an agreement, it will be a lot easier for us to have," he said.

He urged lawmakers on Capitol Hill, as well as the press and the American public to "withhold judgment" until if and when a final agreement is struck.