As Afghanistan's post-war politics begin to take shape, various foreign powers are vying to place their own interests at the top of Kabul's agenda. Among these is Iran, Afghanistan's neighbor to the west and host to at least 1.5 million Afghan refugees.
When it comes to making its voice heard in Afghan political circles, Iran has long had some advantages.
The first is language. Dari, a local dialect of Iran's Farsi language, is the dominant means of communication in Afghanistan.
Then there is religion. An estimated 15 to 20 percent of Afghans follow Shia Islam, the state religion of Iran.
Increasingly, there is money. Iran is helping Afghanistan fight the drug trade, train workers, and build roads and hospitals. Also, many of Afghanistan's imports come from Iran.
Vikram Parekh is the senior Afghan analyst for the policy institute, the International Crisis Group.
"Afghanistan has become a big market for Iran," he said. "Over the past two years, I think it's very easy to see in the shops here in Kabul, Iranian manufactured goods are displacing those that come from Pakistan."
That is a change from the days of Afghanistan's Taleban regime. Iran suffered frosty relations with the Taleban, a strict Sunni Muslim movement from Afghanistan's southeast.
Iran supported the Taleban's main opponents, known as the Northern Alliance.
The Taleban fell from power in 2001, when the United States teamed up with the Northern Alliance, after the Taleban refused to surrender accused terrorist Osama bin Laden.
Today, Northern Alliance commanders retain significant power in Afghanistan. Some are described as "warlords," retaining militias that rule over semi-autonomous states.
Abdul-Hakim Noorzai, a former senior Afghan intelligence official, says these Northern Alliance leaders are Iran's biggest friends.
"I can tell you that all warlords that belong to the Northern Alliance have a very close relationship with the Iranian intelligence service," said Mr. Noorzai.
Several Afghan and foreign officials say Iran has especially strong support from former Northern Alliance commander Ismail Khan, the governor of Herat Province.
A report earlier this month by the Center for Contemporary Conflict, a U.S. Navy research facility, says Governor Khan is among many of the Northern Alliance leaders who have received arms and money from Iran in the past few years. The report says, however, that the governor also has at times shut out pro-Iranian groups trying to influence activities in Herat.
The sources say the relationship with Governor Khan has helped Iran expand its exports to Afghanistan, which cross the border in Herat.
Iran's Foreign Ministry declined an interview for this report, and the Iranian Embassy in Kabul was unavailable to speak on the subject.
But Afghanistan's Deputy Trade Minister Ghulam Nabi Farahi denies that Iran holds any special sway in Afghanistan. He says Teheran does not have any more sway than other countries in the region, and that in general, Afghanistan's foreign policy focuses on free trade and equal relations among all its neighbors.
In terms of grassroots support, Iran would appear to have plenty in Afghanistan. More than half a million Afghan refugees have returned home after sheltering in Iran during their country's two decades of war.
Mr. Parekh with the International Crisis Group notes that at least three times that number of Afghans still live in Iran and are likely to return home.
"This is already having a transformative impact, especially in Herat, Mazar[-e-Sharif] and Kabul, where entire neighborhoods are experiencing a large influx of refugees from Iran," explained Mr. Parekh.
However, he says, Iranian treatment toward the refugees was strict to encourage them to return home as early as possible.
"Refugees had a very subordinate social position in Iran, in which they could be easily arbitrarily detained, in which they were often just held in - well, they were detention centers, but the conditions were sometimes more like concentration camps," he described.
He says, however, that while many Afghans, especially in the west of the country, do have close ties to Iran, they are balanced by the Pashtuns. Many members of Afghanistan's largest ethnic group see Iranian influences as a threat to their own cultural traditions.