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BRUSSELS -- The five permanent members of the U.N. Security Council and Germany, who are demanding that Iran freeze all uranium enrichment, said Tuesday they have accepted an offer to resume talks with Tehran on the nuclear issue.

Responding to a February letter from Iranian nuclear negotiator Saeed Jalili in which he proposed new discussions, EU foreign policy chief Catherine Ashton called for dialogue that would deliver "real progress." Ashton is the contact for the group.

Her announcement comes as the semi-official ISNA news agency reported that Iran said it would grant U.N. inspectors access to a military complex where the U.N. nuclear agency suspects secret atomic work has been carried out.

The EU hopes that Iran "will now enter into a sustained process of constructive dialogue which will deliver real progress in resolving the international community's long-standing concerns on its nuclear program," Ashton's statement said.

The time and venue of the talks have yet to be determined.

The West fears Iran seeks nuclear weapons, and speculation is rife that Israel may launch a pre-emptive strike to set back the program.

Tehran denies that, saying its nuclear program is designed chiefly to generate electricity and does not have a military component. The head of the U.N. nuclear agency said Monday that his organization has "serious concerns" that Iran may be hiding secret atomic weapons work.

Britain's Foreign Secretary William Hague said in a statement that the onus at talks would "be on Iran to convince the international community that its nuclear program is exclusively peaceful."

"Until those actions are taken we will not ease the international pressure on Iran," he said in a statement. Britain's Cabinet were briefed earlier Tuesday by the country's National Security Adviser and intelligence agencies on the latest assessment of Iran's nuclear ambitions.

Talks between Iran and the 27-nation EU have been going on inconclusively for several years.

The last round of negotiations in January 2011 ended in failure.

Ashton had written Jalili in October, offering Iran a new round of talks toward an agreement that "restores international confidence in the exclusively peaceful nature of Iran's nuclear program."

Tehran had previously banned U.N. inspectors from visiting the Parchin installation, southeast of Tehran, but a statement by Iran's permanent envoy to the International Atomic Energy Agency said Tuesday the visit will now be allowed in a gesture of good will.

However, it would require an agreement between the two sides on a guidelines for the inspection, ISNA reported.

Inspecting Parchin was a key request made by senior IAEA teams that visited Tehran in January and February. Iran rebuffed those demands at the time, as well as attempts by the nuclear agency's team to question Iranian officials and secure other information linked to the allegations of secret weapons work.