Condoleezza Rice?s offer of US involvement in multilateral talks with Iran may sharpen debate among Iran?s political elite over the prospect of dialogue with Washington. But her insistence that ?all options?, including threatened military strikes, were on the table will increase the deep scepticism in Tehran over US motives and rally those in outright opposition to any talks.

Even those arguing that any successful negotiations over Iran?s atomic programme must involve the US are likely to reject Ms Rice?s demand that Iran first end all uranium enrichment. Iran?s bottom line for its nuclear programme appears, at the very least, to be continuing the research project resumed in January at the Natanz plant, which enriches uranium in 164 centrifuges.