The United Nations nuclear watchdog says Iran has sharply stepped up its uranium-enrichment drive, tripling its capacity, prompting a cautious expression of concern from Washington even as Russia downplayed nuclear fears as a Western ruse.
The Vienna-based International Atomic Energy Agency (IAEA) says in its latest quarterly report about Iran's atomic activities that it has "major differences" with Iran and "major concerns" about its nuclear program, after inspectors probing suspected weapons work this week returned from a failed mission to Tehran.
The report says the IAEA "continues to have serious concerns regarding possible military dimensions to Iran's nuclear program."
The report by the IAEA says Iran has now made more than 100 kilograms of higher-enriched material, less than half the amount needed for a nuclear warhead.
'Serious Concerns'
In Washington, State Department spokesman Mark Toner declined to comment on the report because it hasn't been publicly released.
"We continue to have serious concerns about Iran's lack of compliance, lack of willingness to meet with the international community about its nuclear program," he said.
The IAEA report will be circulated among member states at their next meeting on March 5. It reportedly details how Iran has carried out a significant expansion of activities at its main enrichment plant near the central city of Natanz, and also increased work at the Fordow underground facility.
Enriched uranium can be used to fuel nuclear power plants, which is Iran's stated aim, or provide material for bombs if refined much further.
At Natanz, the IAEA report said the number of operating cascades -- each of which contains around 170 centrifuges -- has gone from 37 in November to 52 now.
At Fordow, almost 700 centrifuges are now refining uranium to a fissile concentration of 20 percent and preparations are under way to install many more, the report said.
Putin Points Finger At West
Russian Prime Minister Vladimir Putin meanwhile has accused the West of seeking "regime change" in Iran under the guise of trying to prevent the spread of weapons of mass destruction. Putin was speaking as he toured a nuclear research center in the once-secret Russian city of Sarov on February 24.
Russia has not opposed four rounds of UN sanctions aimed at pressuring Tehran, but Moscow has condemned unilateral sanctions imposed by the United States and the European Union over the same nuclear concerns.
It is the latest in an increasingly harsh string of IAEA pronouncements on Iran, which was accused by that agency of secret work "specific to nuclear weapons" in November.
Iran denies seeking a nuclear weapon although many foreign governments suspect it is pursuing such weapons or the capability to make them.
UN Secretary-General Ban Ki-moon said in late January that "the onus is on Iran" to prove that "their nuclear development program is genuinely for peaceful purposes."
The Vienna-based International Atomic Energy Agency (IAEA) says in its latest quarterly report about Iran's atomic activities that it has "major differences" with Iran and "major concerns" about its nuclear program, after inspectors probing suspected weapons work this week returned from a failed mission to Tehran.
The report says the IAEA "continues to have serious concerns regarding possible military dimensions to Iran's nuclear program."
The report by the IAEA says Iran has now made more than 100 kilograms of higher-enriched material, less than half the amount needed for a nuclear warhead.
'Serious Concerns'
In Washington, State Department spokesman Mark Toner declined to comment on the report because it hasn't been publicly released.
"We continue to have serious concerns about Iran's lack of compliance, lack of willingness to meet with the international community about its nuclear program," he said.
The IAEA report will be circulated among member states at their next meeting on March 5. It reportedly details how Iran has carried out a significant expansion of activities at its main enrichment plant near the central city of Natanz, and also increased work at the Fordow underground facility.
Enriched uranium can be used to fuel nuclear power plants, which is Iran's stated aim, or provide material for bombs if refined much further.
At Natanz, the IAEA report said the number of operating cascades -- each of which contains around 170 centrifuges -- has gone from 37 in November to 52 now.
At Fordow, almost 700 centrifuges are now refining uranium to a fissile concentration of 20 percent and preparations are under way to install many more, the report said.
Putin Points Finger At West
Russian Prime Minister Vladimir Putin meanwhile has accused the West of seeking "regime change" in Iran under the guise of trying to prevent the spread of weapons of mass destruction. Putin was speaking as he toured a nuclear research center in the once-secret Russian city of Sarov on February 24.
Russia has not opposed four rounds of UN sanctions aimed at pressuring Tehran, but Moscow has condemned unilateral sanctions imposed by the United States and the European Union over the same nuclear concerns.
It is the latest in an increasingly harsh string of IAEA pronouncements on Iran, which was accused by that agency of secret work "specific to nuclear weapons" in November.
Iran denies seeking a nuclear weapon although many foreign governments suspect it is pursuing such weapons or the capability to make them.
UN Secretary-General Ban Ki-moon said in late January that "the onus is on Iran" to prove that "their nuclear development program is genuinely for peaceful purposes."