U.N. nuclear inspectors were granted access to a high-security military site in Iran and were permitted to meet senior personnel at the facility, an Iranian official said Sunday.

Meanwhile, Iranian President Mahmoud Ahmadinejad (search) told visiting Iraqi Deputy Prime Minister Ahmad Chalabi (search) that Tehran supports Iraq's territorial integrity and believes a powerful government in Baghdad is in Iran's interests. He also called for expediting the construction of an oil pipeline and railway between the once-bitter foes.

Foreign Ministry spokesman Hamid Reza Asefi said the U.N. inspectors were allowed to visit the Parchin military site about 20 miles southeast of Tehran after they arrived in Iran on Oct. 28 for a weeklong visit. U.S. officials claim the facility may be part of Iran's nuclear arms research program.

Iran denies claims that its nuclear program is aimed at building nuclear weapons.

The visit followed repeated efforts by the U.N.'s nuclear watchdog, the International Atomic Energy Agency (search), to return to the site after a previous inspection in January. Inspectors wanted to conduct further checks of radioactivity in buildings and areas within the sprawling military complex.

If the samples taken from objects in Parchin reveal minute amounts of radioactivity, it would strengthen suspicions of nuclear-related work at the site, which is run by the Iranian armed forces. The January visit revealed no such traces.

"This time they asked to visit other areas of the site," Asefi told reporters during a news conference. "They talked with our friends this time. What they have done in Iran has been in the framework of the NPT (Nuclear Nonproliferation Treaty)."

With the next IAEA board meeting only weeks away, Iran is under increasing pressure to show it is cooperating with a U.N. probe of its suspected nuclear weapons activities as it tries to derail a U.S.-backed European push to report it to the Security Council.

The IAEA thus far has found no firm evidence to challenge Iranian assertions that its military is not involved in nuclear activities.

Also Sunday, Ahmadinejad assured Iraq's deputy prime minister that it supports its territorial integrity and independence.

"The Islamic Republic of Iran believes that establishing peace and security in Iraq requires having a powerful government with popular support more than anything else," Ahmadinejad was quoted as telling Chalabi on television Sunday.

The U.S. has accused Iran of not doing enough to stop militants entering Iraq to wage attacks inside the war-ravaged country. Iran denies the claims.

Chalabi's visit to Iran is seen as a boost for Tehran, which has been the focus of international criticism after Ahmadinejad recently said Israel should be "wiped off the map." Earlier this week, U.N. Secretary General Kofi Annan canceled a planned trip to Iran over the remarks.

Relations have improved markedly between Iran and Iraq following the 2003 toppling of Saddam Hussein, who led Iraqi forces into an eight-year war with Iran that ended in 1988 and killed more than 1 million people on both sides.

Ahmadinejad said Iran was willing to offer its experience and expertise to rebuild Iraq and insisted on expediting work to set up an oil pipeline between Iran's port city of Abadan and Basra, Iraq's second largest city.

Ahmadinejad also called for completing a railway project connecting both countries. He said Iraq could use Iranian ports as a transit route to export goods.