Iran must prove nuke ambitions peaceful

Iran has yet to prove to the world it wants a peaceful nuclear programme, top US diplomat John Kerry said yesterday, warning with his French counterpart that gaps still had to be overcome to clinch a deal.

"Critical weeks" lie ahead as a March 31 deadline looms to seal a political framework on reining in Iran's suspect atomic programme, Kerry said after meeting with French Foreign Minister Laurent Fabius.

"We want an agreement that's solid," Kerry told reporters ahead of four-way talks to also include German Foreign Minister Frank-Walter Steinmeier and their British counterpart Philip Hammond.

"We want an agreement that will guarantee that we are holding any kind of programme that continues in Iran accountable to the highest standards so that we know in fact that it is a peaceful programme."

The US secretary of state flew in from London on the last stop of a week-long trip to brief his European counterparts on the state of the negotiations.

France has privately expressed concern that Washington could be rushing into a deal without ensuring iron-clad guarantees are in place to stop Tehran acquiring a nuclear bomb. But in a show of unity, Kerry said he had "the same assessment" as Fabius.

"We have made progress, but there remain gaps, divergences as he (Fabius) said, and we need to close those gaps," Kerry insisted.

"And that is our goal over the course of the next days. We have a critical couple of weeks ahead of us."