Afghan President Hamid Karzai admitted at a press conference Monday that his office accepts "bags of money" from the Iranian government.

That acknowledgment brings into the open two uncomfortable facts confronting the U.S. plan to build a modern democracy in Afghanistan. As it's done in Iraq, Iran is successfully buying influence with Afghan leaders, and Karzai — like many members of Afghanistan's political class — considers bags of cash a legitimate tool of statecraft.

The United States, of course, does, too, and funnels tens of millions of dollars a year into Afghanistan to influence the country's internal affairs — even paying "salary supports" to a wide range of Afghans officials.

Iran's efforts may extend beyond Karzai's palace, as Washington's do. Members of the Afghan parliament say other politicians are taking Iranian money, and recent media reports charge that the Iranians are paying the Taliban to kill U.S. soldiers, although Shiite Muslim Iran and the militant Sunni insurgents are enemies.

What does Iran want for its bags of cash? First and foremost, Iran wants pressure put on international forces to leave its doorstep.

"The Iranians are happy with the Karzai regime being established in Afghanistan — in this way, the U.S. and Iran are aligned. But when it comes to international forces in Afghanistan, the Iranians are quite unhappy about this," said Waliullah Rahmani, the head of the Kabul Center for Strategic Studies.

The U.S. invasions of Iraq and Afghanistan put American forces on the ground on either side of Iran. In Afghanistan, U.S. forces at Shindand Airbase are less than 75 miles from the Iranian border.

Iranian President Mahmoud Ahmadinejad has called for the withdrawal of American forces from Afghanistan as a means of stabilizing the region.

While the wars in Iraq and Afghanistan have inadvertently strengthened the regional clout of U.S.-foe Iran, Tehran and Washington share an ally in Karzai, since both nations oppose a Taliban resurgence.

When they were in power, the Taliban killed Iranian diplomats and oppressed the Afghanistan's Shia minority. The country's new Constitution, written after the U.S.-led invasion, recognizes the rights of the Shiites for the first time in Afghanistan's history. Karzai's government also includes members of the Northern Alliance, whom Iran supported in previous decades.

"It is not a strategic policy of the Iranians to support the revival of the Taliban in Afghanistan," says Mr. Rahmani. "But tactically, in some areas, in order to weaken the international forces there are media reports that the Iranians have supported the Taliban."

Karzai, responding to a New York Times report alleging that his chief of staff received money from Iranian officials, said his office takes Iranian payments of $700,000 to $975,000 once or twice a year to cover presidential expenses.

But "when it comes to giving bags of cash to the office of the president, this is something that will shock some people," said Fawzia Kofi, a member of parliament. "If Iran would like to support some projects like education, they are more than welcome to do so. But not by giving bags of cash without proper checks and balances and transparency," she said.

Kofi and retiring parliamentarian Sabrina Saqib said that they've heard many stories of parliamentary candidates receiving Iranian money.

"They are worried that Afghanistan will agree with having a base for American troops here," Ms. Saqib told the Monitor last month. Iran wants friendly lawmakers to head off any legislation that would grant permanent basing rights. "They are trying to have people around who — if this would be the case — they would disagree."

Afghanistan has a significant Shiite minority, most of whom are ethnic Hazaras who suffered harsh persecution during Taliban rule, which has led to a strong reservoir of support for the NATO mission in that community. Areas under Hazara control have seen the least armed resistance to the international military presence. For example, New Zealand troops in Bamiyan province have encountered only one hostile incident in the past nine years.

"A majority of this community is trying to make distance from the Iranians in trying to be with those democratic forces who are pushing for the dominance of a stable democracy," says Rahmani, himself a Hazara. "You cannot see any demands of the Hazaras for the withdrawal of international forces."

(Arnoldy is a Christina Science Monitor staff writer.)