"The Americans have recently contacted Iran through different channels requesting talks about Iraqi issues and in particular that country's security," Mohammad Ali Hosseini told state television.

"We are studying these proposals," he added.

Hosseini did not specify if he was referring to a security conference on Iraq planned for March, which is set to include both the United States and Iraq's neighbours including Iran.

"We are ready to put all our resources at the Iraqi government's disposal to improve stability and security," the spokesman added.

Iran's top security official Ali Larijani said last week that Tehran would take part in the conference so long as it was in the interests of its violence-plagued neighbour.

Iran and the United States have had no diplomatic relations since Washington severed ties in 1980 in the wake of the seizure of its embassy in Tehran by Islamist students.

Any official contacts between the two sides would mark a major break in the frozen relations, which have been marked by mutual recriminations and enmity over almost three decades.

Washington, which has repeatedly accused Tehran and its close ally Damascus of fomenting the violence in Iraq, said it would join the conference and would not rule out possible contacts between US envoys and Iranians.

The move is seen as a potential policy shift for the United States, which also accuses Iran of seeking to develop nuclear weapons and is leading an international campaign to force Tehran to stop its controversial nuclear work.

But the White House has rejected bilateral talks with Iran and Syria amid speculation that joining the conference together with these two countries was a sign of Washington's warming toward the two US arch-rivals in the Middle East.

Meanwhile, senior US and European officials indicated Friday that new UN sanctions being drawn up against Iran to curb its nuclear programme will involve only a relatively minor tightening of measures imposed by the world body in December.

"This is going to be an incremental resolution," said State Department spokesman Sean McCormack.

"It will be proportionate to the response that the Iranians have given the international community to this point," he told reporters as diplomats from the big five UN Security Council states plus Germany pursued talks on the new resolution.