Iran is continuing to raise the stakes in the continuing diplomatic standoff over its nuclear intentions. On Thursday, shortly before the arrival of the head of the International Atomic Energy Agency (IAEA) in Tehran, Iranian President Mahmoud Ahmadinejad insisted that the country had no intention of halting work on its nuclear program.

The timing could hardly be more  inauspicious. Two days after Iran announced that it had succeeded in enriching uranium, Mohamed ElBaradei arrived in the Iranian capital to persuade the hardline regime to do just the opposite: halt its enrichment program and thus come into compliance with the United Nations Security Council ultimatum  issued at the end of March, which called on Tehran to cease its efforts to enrich uranium within 30 days.

If there were any remaining doubts about the regime's defiance, the Iranian President made things quite clear. Speaking late on Wednesday evening, Ahmadinejad said: "Our answer to those who are angry about Iran obtaining the full nuclear cycle is one phrase, we say: Be angry and die of this anger." He added, "We will not hold talks with anyone about the Iranian nation's right to enrich uranium."

ElBaradei is in Tehran for talks aimed at defusing the current stand-off. He said he hoped to convince Iran to suspend its uranium enrichment "until outstanding issues are clarified." On his arrival in the Iranian capital he said that he was looking for more "active co-operation" between Iran and the IAEA.

ElBaradei's first meeting was with Gholamreza Aghazadeh, the head of Iran's Atomic Energy Association. Speaking afterwards, Aghazadeh said "Of course, the discussions were very serious and we brought up many, many topics. We also complained about their (IAEA's) performance." ElBaradei is also expected to meet Ali Larijani, secretary of Iran's Supreme National Security Council. After the first round of meetings ElBaradei said that he could not yet confirm if Iran had actually enriched uranium to 3.5 percent, as it had claimed. "I cannot confirm that. Our inspectors have taken samples. They will report to the board," he said.

Tensions have risen after Iran announced on Tuesday that it had produced enriched uranium  on a small scale for the first time, using 164 centrifuges, at a facility in Natanz. The announcement was interpreted as a provocation by many in the West. At the end of March, the UN Security Council had asked Iran to halt its enrichment activities by April 28. ElBaradei is expected to report to the Security Council by the end of April on whether Tehran is complying with this demand.

The West suspects that Iran wants to develop a nuclear weapon, although Tehran insists that its plans are only for a civilian nuclear energy program.

There seems to be less and less room for compromise. An IAEA diplomat in Vienna told Reuters that it was "wishful thinking" to think that Iran would shut down the nuclear process entirely now: "They have obviously achieved a significant advance at the research and development level and want to present it as a fait accompli to strengthen their bargaining position."

On Wednesday, UN Secretary General Kofi Annan said he hoped that ElBaradei would be able to persuade Iran to resume negotiations. "They have pursued their research but I hope they will be able to come back to the table and work with the international community to find a negotiated solution." He also appealed to all sides to "work more actively in search of a diplomatic solution and to cool down the rhetoric."

The scene is now set for more diplomatic manoeuvres. China has announced that it will send an envoy, Assistant Foreign Minister Cui Tiankai, to both Tehran and Moscow in an attempt to diffuse the current crisis. Meanwhile, the United States and France have both indicated that they will be taking a tough line. Washington said the United Nations should take "strong steps" against the Iranians. French Foreign Minister Philippe Douste-Blazy, speaking on the German radio station RTL, said that if Iran did not fulfil the international community's demands, the Security Council would take "the necessary measures."