Straw insisted that there were no parallels with the campaign against the proliferation of weapons of mass destruction that led to the Anglo-American war against Iraq.

"I can conceive of no such circumstances" in which military action will be used against Iran, Straw said in a telephone interview with the BBC from Tehran.

"No one should ever compare Iran with Iraq in terms of the political system or their danger," he stressed ahead of his meeting with Iranian President Mohammad Khatami.

The British Foreign Secretary told the BBC that "nobody knows for certain" whether Iran has nuclear weapons and that the issue was about "developing confidence" and Iran signing additional protocols on the Non-Proliferation Treaty.

In return, he said, Tehran was seeking "progress on lifting sanctions and so on" but he insisted that this is a sequential issue and not just an area for bargaining.

The Foreign Secretary, on his fourth visit to Tehran in less than two years, suggested that Britain was willing to try to put pressure on Iran by seeking the support of the European Union to threaten to delay its prospective Trade and Cooperation Agreement.

Britain, he said, had "insisted in the EU that this is linked with progress with the IAEA (International Atomic Energy Authority)." He also claimed Russia, which has been cooperating with some nuclear civilian technology, was "getting increasingly impatient" with Iran.

Iran says Straw visit was "necessary"

"The visit of Mr. Straw was necessary because closing the doors would solve nothing and it is not an appropriate method to convey our viewpoints and positions to our European friends through the media," Asefi told reporters at his weekly press briefing.

He said Straw and Iranian officials had discussed the stances of Tehran and London on various issues, admitting that there existed differences of opinion in certain areas.

"Mr. Straw explicitly spelled his views out and we too declared ours," he said.

Asefi further said that Iran was ready to continue talks with the International Atomic Energy Agency (IAEA) on its nuclear programs, but said any decision on signing an additional protocol of the nuclear Non-Proliferation Treaty (NPT) depends on lifting the sanctions against Iran.

"We have no problem in continuing our talks with IAEA and Europe, and are ready to consider the concerns of the European states in this connection, but this can never be a 'one-way road' as both sides must work to remove the due concerns," he said.

"It must be verified what will happen when Iran signs the 93+2 Protocol ... Our European friends must clarify this."

Asefi said the European states should not highlight certain articles of the NPT that benefit them and ignore those which make them committed toward Iran.

"The European states must consider their responsibilities because progress could be made only through mutual confidence and understanding," he said.

Asked what Iran would do now that Straw has given no guarantee on lifting of the sanctions in return for Iran's signing of the additional protocol, he said: "Tehran would also give no guarantee to sign the NPT protocol."

Straw arrived in Tehran Sunday afternoon on his fourth visit to the Islamic Republic in less than two years.

In a press conference with his Iranian counterpart Kamal Kharrazi Sunday evening, the British official called on Iran to sign the NPT additional protocol.

However, he said he could not say when the sanctions against Iran would be lifted. Tehran has conditioned the signing of the protocol to the lifting of the economic sanctions against Iran.