Vienna,: Iran and the US held one-on-one talks on Wednesday as a deadline loomed to reach a mammoth nuclear deal, seeking common ground on the two crucial remaining issues: uranium enrichment and sanctions relief.
US Secretary of State John Kerry and other foreign ministers from the six powers meanwhile decided to hold off for at least another 24 hours joining the final round of negotiations before Monday's cut-off point.
Kerry remained in London before talks in Paris tomorrow with the foreign ministers of France -- widely seen as one of the six powers with the toughest stance on Iran -- and of Saudi Arabia, itself no friend of Iran.
Russian Foreign Minister Sergei Lavrov, whose country is a crucial player in the talks, will only attend if there is sufficient progress, Moscow's lead negotiator Sergei Ryabkov told Russian media.
"Right now a lot depends on Kerry's visit. Reaching a deal depends on the willingness and ability of the United States to lift sanctions" on Iran, RIA Novosti quoted a Russian source as saying.
Upping the ante, Iran's Foreign Minister Mohammad Javad Zarif, who has been in Vienna since yesterday, said a deal was "possible" but only if the six powers did not ask for too much.
That view was echoed today by President Hassan Rouhani.
"If the other side shows the political will to reach an accord and doesn't make excessive demands, a deal could be done," he said on his website.
But Kerry, who held the latest in a string of meetings with Zarif in Oman last week, put the onus on Iran.
"It is imperative that Iran works with us with all possible effort to prove to the world that the programme is peaceful," Kerry said in London yesterday.
The landmark accord being sought by Monday's deadline, after months of negotiations, is aimed at easing fears that Tehran might develop nuclear weapons under the guise of its civilian activities -- an ambition it denies.
It could resolve a 12-year standoff, silence talk of war, help normalise Iran's relations with the West and mark a rare foreign success for US President Barack Obama.
"A deal is in everybody's interest because it could improve the troubled global economy by making use of Iran's major economic capacities," Rouhani said in his statement.
In order to make it virtually impossible for Iran to assemble a nuclear weapon, the US, China, Russia, Britain, France and Germany (the P5+1) want Iran to scale down its nuclear programme.
Some areas appear provisionally settled, such as the future of the Arak nuclear reactor and tighter UN inspections to better detect any attempt to build a bomb.