ABOARD AIR FORCE ONE (REUTERS) - The United States would not sign on to an agreement over Iran's nuclear programme that would threaten Israel, the White House said on Friday, one day after negotiators in Switzerland announced a framework for a nuclear deal.

Earlier on Friday, Prime Minister Benjamin Netanyahu said it demanded that any final agreement with Iran acknowledge his state's right to exist.

Asked about the demand, White House spokesman Eric Schultz said he had not seen the specific request but was aware of Israel's ongoing concerns.

"We understand his position," Schultz told reporters aboard Air Force One. "The President would never sign onto a deal that he felt was a threat to the state of Israel."

Meanwhile, Iranian President Hassan Rouhani, in a televised speech, on Friday hailed the framework as "a first step towards productive interactions with the world."

Schultz, asked about Rouhani's comments, said he understood Teheran's need to sell the deal to Iranians but that the United States sees the deal as one focused on Iran's nuclear programme.

"The concerns we have with Iran outside of the nuclear programme remain just as vibrant... yesterday as they are today."

Schultz also said President Barack Obama was continuing his outreach to US lawmakers over the tentative agreement and planned to speak with all four leaders of Congress.

He did not give details on the timings of those talks with the leaders in the US House of Representatives and the Senate - Republican House Speaker John Boehner, House Democratic Leader Nancy Pelosi, Republican Senate Majority leader Mitch McConnell and Senate Democratic Leader Harry Reid - but said Obama aimed to talk to them on Friday.