Six world powers did not offer to suspend oil or financial sanctions during talks with Iran on its nuclear programme in the Kazakh city of Almaty, a senior US administration official said on Wednesday.

The powers - France, Germany, the United States, China, Russia and Britain - offered at the talks to lift some sanctions if Iran scaled back nuclear activity the West fears could be used to build bombs. Iran denies any such aim.

"None of (the) oil and none of (the) banking sanctions (are) touched," the US official said, referring to the punitive steps which are having the biggest impact on Iran's economy.

Iran had earlier said the February 26 - 27 talks in Almaty represented a "positive step". They will be followed by meetings in March and April.

But the US official made clear that Washington wants to see concrete action to address growing international concerns about Tehran's nuclear programme, which Iran says is for peaceful energy purposes.

The official, who declined to be identified, said the meeting was "useful" as the two sides agreed on dates and venues for their next meetings - at expert level in Istanbul in March 18 and a new round of political talks in Almaty on April 5-6. – Reuters