Iran's nuclear programme

SHANNON, Ireland — US State Department official William Burns has insisted the United States feels a "sense of urgency" towards Iran's nuclear programme, as he headed to Russia for a two-day visit.

"We feel a sense of urgency, it's time to demonstrate that there are consequences" to Tehran's behaviour, said the under secretary for political affairs Wednesday who is accompanying US Secretary of State Hillary Clinton.

The US and Russia "steadily expand the common ground between us on Iran, and we work effectively together," said a senior US official, speaking on condition of anonymity, ahead of the Moscow visit which starts Thursday.

Washington is working towards sanctions which "minimize the impact on the Iranian people and maximize the chances of the Iranian leadership to make the right choices," said the official.

Trying to push through new international sanctions against Tehran was a complex process, said the official, but added that "we do share an interest with the Russians."

Russia, the United States, France, Britain, China and Germany have been putting pressure on Iran over its nuclear programme, amid fears that Tehran is trying to build a nuclear weapon.

Of the six, China continues to resist imposing fresh sanctions while Moscow slowly appears to be coming over to the other countries' tougher stance on the issue.

Burns also insisted again that the US and Russia were "getting closer" to an agreement on a nuclear disarmament treaty to succeed the 1991 Strategic Arms Reduction Treaty (START), which expired in December.

The accord led to huge reductions in the US and Russian nuclear arsenals and imposed verification measures to build trust between the two former Cold War foes.

"The leadership the US and Russia show on this sends an important message about other questions, like non-proliferation," said a second senior US official, also speaking on condition of anonymity.

One year after President Barack Obama urged a "reset" of strained relations between the US and Russia, the official said "over a hundred flights" from the US military had already passed through Russia towards Afghanistan.

This was a result of a decision taken by Obama and his Russian counterpart Dmitry Medvedev, said the diplomat.