VIENNA, Jan 5: Ending a months-long standoff, the UN atomic agency will visit "within the next few weeks" Iran's Parchin military facility where the United States charges that Tehran is simulating testing of atomic weapons , the agency's chief Mohamed ElBaradei said on Wednesday.

"We expect to visit Parchin within the next few weeks," Mr ElBaradei said. The International Atomic Energy Agency (IAEA) has been trying to gain access to Parchin since July.

Iran denies carrying out any nuclear-related work at Parchin, a huge military complex 30 kilometres southeast of Tehran. A senior US official said the United States was concerned about high-explosives testing in Parchin that may "amount to (nuclear) weapons intent".

The official said the Iranians may be working on testing "high-explosive shaped charges with an inert core of depleted uranium" as a sort of dry test for how a bomb with fissile material would work.

Parchin is a site for a variety of defence projects, including Defence Industries Organization (DIO) work in chemical explosives. Iran maintains that its nuclear program is strictly civilian and peaceful and that it is not developing atomic weapons.

Parchin is an example of a so-called "transparency visit", where the IAEA is going beyond its mandate under the nuclear Non-Proliferation Treaty (NPT) to check to see if nuclear materials have been diverted away from peaceful use.

There could very well be no nuclear material at Parchin, since the concern there is of weapons simulation testing. The other problem is that Parchin is a military site, to which access is more difficult.

"The important thing is for us to go make sure that there is no (nuclear) material there," Mr ElBaradei said. But he also said: "We are trying to push the envelope as far as we can go."

"Within our authority, I can tell you we are trying every possible way to push the envelope, and Parchin would be a perfect example of that," Mr ElBaradei said.

"We are trying to understand if there is any linkage to a weapons program," he said. The long quest to visit Parchin has also brought forth charges that Mr ElBaradei is collaborating with Iran, charges he has heatedly denied. -AFP