The new Obama administration is willing to talk to Iran "without preconditions" and will work towards the abolition of nuclear weapons, the White House said today.

The Obama foreign policy agenda that appeared on the White House website said: "Barack Obama supports tough and direct diplomacy with Iran without preconditions," the policy outline said. The Bush administration made direct talks between the US and Iran conditional on Iranian suspension of its uranium enrichment programme. This step breaks that conditionality, as part of a fundamental shift in diplomatic approach. The Obama agenda said the new administration will "talk to our foes and friends" and not set preconditions.

However, talks with Iran will be "tough and direct", and will put on the table the same deal that the international community has been trying to get Tehran to accept for the past four years: extensive economic and diplomatic help if uranium enrichment is suspended, further economic pressure and diplomatic isolation if it does not. Iran has resisted this carrot-and-stick approach so far, despite four sets of UN sanctions, but western diplomats hope that direct engagement by Washington will help break the impasse.

"In carrying out this diplomacy, we will coordinate closely with our allies and proceed with careful preparation," the White House said. "Seeking this kind of comprehensive settlement with Iran is our best way to make progress."

The other notable shift in US foreign policy announced today was a strategic decision to move towards a "nuclear free world", through bilateral and multilateral disarmament. "Obama and [Vice President Joe] Biden will set a goal of a world without nuclear weapons, and pursue it," according to the agenda. It is a long term goal. The US will maintain a "strong deterrent as long as nuclear weapons exist", but begin to take steps on the "long road towards eliminating nuclear weapons".

The development of new nuclear weapons will be stopped, a sharp change from the Bush administration that pushed for a new generation of warheads, and the new administration will work with Moscow to take US and Russian missiles off their current hair trigger alert, while seeking "dramatic reductions in US and Russian stockpiles of nuclear weapons and material".

The new nuclear agenda is closely in tune with British policy, since the former foreign secretary, Margaret Beckett, announced Britain's backing for nuclear abolition in 2007. The UK claims to have reduced the total explosive power of its nuclear arsenal by 75%.

A new foreign policy paper due to be made public next month lays out methods for the world to reduce the risk of proliferation, and work towards a nuclear free world, particularly by increasing international confidence in verification techniques, so nations can be sure their rivals are not secretly arming themselves.

"The UK is working to build a broad coalition of governments, international organisations, non-governmental organisations and businesses which share the vision of a world free of nuclear weapons and to forge agreement on how we will work together to make it happen," the policy paper will say.