It also lashes out at Britain and France for "ill will and political motivation" in their dealings on Iran.
Iranian envoy Ali Asghar Soltanieh sent the letter to Mohamed ElBaradei, the head of the International Atomic Energy Agency, whose 35-nation board will take a hard new look at Iran's nuclear program next week.
Iran insists its nuclear activities are peaceful and geared solely toward generating electricity. The US and key allies contend the Islamic republic is covertly trying to build an atomic bomb.
Teheran has bristled at the agency's latest report, which accuses Iran of defiantly continuing to enrich uranium and refusing to clear up lingering questions about possible military dimensions to its nuclear program.
But it takes sharp aim at Washington for giving the UN nuclear watchdog unspecified intelligence and other evidence allegedly recovered from a laptop computer that reportedly was smuggled out of Iran.
US intelligence later assessed the information as indicating that Teheran had been working on details of nuclear weapons, including missile trajectories and ideal altitudes for exploding warheads.
The material on the laptop also included videos of what intelligence officials believe were secret nuclear laboratories in Iran.
"By interfering in the work of the IAEA and exerting various political pressures, the government of the United States attempted to spoil the cooperative spirit between the Islamic republic of Iran and the IAEA," the letter reads.