Iran has sent a formal protest letter to the United States, accusing it of spying on Iran's nuclear activities.
Iran says its nuclear programme is for power generation
Foreign Minister Manouchehr Mottaki said the note was sent in response to a US intelligence report released on Monday about Iran's nuclear activities.
It said Iran had a weapons programme until 2003, but overturned the view that the programme was still active.
Mr Mottaki said the report included "facts and lies", denying that Iran had ever had a nuclear weapons programme.
"Seventy percent of the US intelligence report is true and positive and the remaining 30%, in which they claim that Iran had a nuclear weapon programme before 2003, is wrong," he said in an address to university students on Saturday.
"They refused to confess about this 30% because they did not want to lose all their reputation or for similar reasons."
Mr Mottaki said the report contained 'facts and lies'
Mottaki said the US intelligence report revealed the extent of US use of surveillance satellites and other espionage activities.
He said the foreign ministry had written to the Swiss Embassy, which handles US-Iranian relations as there is no US diplomatic presence in Tehran, on Monday, the day the report was released.
The letter had called for "explanations on the US espionage", he said.
The declassified summary of the National Intelligence Estimate said US intelligence agencies now believe that Iran is enriching uranium and may be able to build a nuclear bomb in three to eight years time, but does not have an active weapons programme.
Iran welcomed the report, but the US said the country remains a threat.
Washington called on the international community to maintain pressure on Iran to stop enriching uranium - a process which can be used to produce a key ingredient for a nuclear bomb.