Iran said Tuesday that it will allow the UN's nuclear watchdog to inspect Parchin military base, while the EU announced its acceptance to resume nuclear talks with the Islamic republic.

A statement of the International Atomic Energy Agency (IAEA) said Iran will allow its experts to visit Parchin military base, the semi-official ISNA news agency reported.

"The IAEA member states are expected to support this process and avoid the measures that may weaken the successful outcomes," the statement was cited as saying.

It further said that in 2005, the IAEA officials visited Parchin twice, according to ISNA.

An earlier IAEA report said that some "activities" are being carried out in Parchin in southeastern Tehran, which are suspected as possible controversial weapons development.

The IAEA head said Monday that Iran has stepped up its nuclear enrichment activities, as its monthly production of 20-percent purity uranium has tripled since November.

Speaking at the quarterly meeting of the IAEA board, Yukiya Amano said the UN nuclear watchdog has "serious concerns" that Iran's heightened enrichment activities may relate to the development of nuclear weapons.

Amano also highlighted Iran's repeated refusal to allow inspectors into Parchin military site, in which simulated nuclear warhead tests allegedly took place.

Earlier, Ali Asgar Soltanieh, Iran's envoy to IAEA, told reporters that access to Parchin would only be granted if Iran and the IAEA agree on certain conditions.

On Monday, Soltanieh described Amano's remarks on Tehran's nuclear program as a repetition of his previous statements, the local satellite Press TV reported.

Despite that the recent two rounds of talks with Iran produced no substantive results, the IAEA chief said the agency would continue to address the Iran nuclear issue through dialogue and in a consultative spirit.

"The basic objective is to resolve all outstanding issues, in particular those related to possible military dimensions to Iran's nuclear program, and restore confidence in the peaceful nature of Iran's nuclear activities without further delay, " Amano said.

On Tuesday, EU foreign policy chief Catherine Ashton said she has accepted an Iranian offer to discuss Tehran's disputed nuclear program.

"I have offered to resume talks with Iran on the nuclear issue, " Ashton said in a statement, referring to Iran's offer in February to resume talks with global powers.

"We hope that Iran will now enter a sustained process of constructive dialogue which will deliver real progress in resolving the international community's long-standing concerns on its nuclear program," she said on behalf of the six powers that are involved in the nuclear talks with Iran, namely the United States, Russia, China, Britain, France and Germany.

According to the statement, the time and venue of the talks has not been decided yet.

In her letter to Iran's chief nuclear negotiator Saeed Jalili, Ashton said that the talks should focus on "building confidence by developing concrete and practical steps."

"These confidence building steps should form first elements of a phased approach which would eventually lead to a full settlement between us, involving the full implementation by Iran of UN Security Council and IAEA Board of Governors' resolutions," the letter read.

Asthon's offer to resume talks came weeks after the bloc decided on additional sanctions on Tehran, focusing on its central bank and oil exports.

The West accuses Iran of attempting to develop nuclear weapons, but the latter denies that and says its nuclear program is for peaceful purposes.