The Iranian foreign minister has said he believes an agreement with world powers on Iran's nuclear programme is possible by the end of talks on Friday.

Mohammad Zarif told CNN that Iran would not suspend uranium enrichment completely but could "deal with the various issues on the table".

The foreign powers did not comment on the progress of the talks in Geneva.

US Secretary of State John Kerry, currently on a tour of the Middle East, is due to attend discussions on Friday.

The BBC's Kim Ghattas, who is travelling with Mr Kerry, says his dramatic decision to change his travel plans and go to Geneva is a clear sign that a deal with Iran may be within reach.

On Thursday, the US confirmed some sanctions relief was being offered in return for "concrete, verifiable measures".

Israel's Prime Minister, Benjamin Netanyahu, has said a nuclear deal would be a "historic" mistake, accusing Iran of only offering fake concessions.

The five permanent UN Security Council members plus Germany (P5+1) opened two days of talks with Iran on Thursday.

The West suspects Iran's uranium enrichment programme is a step towards building nuclear weapons.

'End game'

Mr Zarif said the sides could sit down by Friday morning to prepare "some sort of a joint statement" that would address three elements: a common objective, an "end game... in less than a year'' and mutual confidence-building measures.

He has talked of a "three-phase plan" previously.

Iran's lead negotiator, Deputy Foreign Minister Abbas Araqchi, said the world powers had "clearly" accepted his country's proposed framework and were now discussing details.

However, there was no official confirmation from the P5+1 - the US, Russia, China, the UK, France and Germany.

In Washington, White House spokesman Jay Carney told reporters that the six powers "would consider limited, targeted, and reversible relief that does not affect our core sanctions architecture".

The broader sanctions regime would be maintained until there was a "final, comprehensive, verifiable" agreement that resolved international concerns, he said.

If Iran failed to show progress on its nuclear programme, the "moderate" sanctions relief could be reversed, and stiffer sanctions could be imposed, he added.

Hopes of a long-awaited deal on curbing Iran's nuclear ambitions were given fresh momentum this year by the election of President Hassan Rouhani, seen as a relative moderate.

Since 2006 the UN Security Council has imposed a series of sanctions - including asset freezes and travel bans - on entities and people involved in Iran's nuclear programme.

Separate US and EU sanctions have targeted Iran's energy and banking sectors, crippling its oil-based economy. Iran wants the sanctions lifted.

Israeli warning

Speaking at a conference in Jerusalem before the talks began, Mr Netanyahu said the proposals would allow Iran to retain the capabilities to make nuclear weapons.

"Israel understands that there are proposals on the table in Geneva today that would ease the pressure on Iran for concessions that are not concessions at all," he said.

"This proposal would allow Iran to retain the capability to make nuclear weapons.

"Israel totally opposes these proposals. I believe that adopting them would be a mistake of historic proportions. They must be rejected outright."

Mr Netanyahu said economic sanctions had brought the Iranian economy to the "edge of the abyss" and the P5+1 could "compel Iran to fully dismantle its nuclear weapons programme".

"Anything else will make a peaceful solution less likely. Israel always reserves the right to defend itself, by itself, against any threat," Israel's prime minister said.