Iran has begun funneling money and weapons to one of Afghanistan's most unpredictable warlords, a move that could further destabilize a country where order remains fragile at best, according to government authorities here in the Afghan capital.

Abdurrashid Dostum, who rules the strategic northern city of Mazar-e Sharif, has been provided cars, trucks, firearms, ammunition and cash for his soldiers, two senior intelligence officials in Afghanistan's interim central government said in separate interviews this week.

At a time when the new Afghan government is struggling to extend its authority throughout the country, an Iranian supply line could enable Dostum to expand the territory under his control. On the other hand, curtailing Dostum's regional dominance could greatly strengthen the government's position.

An Iranian diplomat denied that his country was aiding Dostum.

However, the intelligence reports could fuel concerns here and in Washington about Tehran's attempts to influence post-Taliban Afghanistan at the expense of the interim government. U.S. and Afghan officials already have accused Iran of meddling in areas of western and southern Afghanistan. President Bush has warned Iran not to interfere in its neighbor's internal affairs and last week branded it part of an "axis of evil," along with Iraq and North Korea.

"Iran doesn't want Afghanistan to be stable," said the chief military investigator for the Kabul government, Keram, who like many Afghans uses one name. "They don't want the [peacekeeping] program of the U.N. to be implemented, and they don't want there to be a country supported by the West."

An Iranian alliance with Dostum would present a major new challenge to Hamid Karzai, the leader of the interim Afghan government, as he tries to rein in factional leaders while smoothing over prickly relations with neighboring countries that support them. Today Karzai flew to the western city of Herat to meet with warlord Ismail Khan, who also allegedly has been receiving assistance from Iran -- a claim that Iran, a longtime ally of Khan's, has denied.

But in many assessments, Dostum poses a greater threat to national cohesion than Khan does. Known for his brutal methods, the ethnic Uzbek warlord repeatedly betrayed allies during nearly every phase of Afghanistan's 23 years of war and has been linked to some of the period's bloodiest massacres.

Dostum ostensibly was a member of the Northern Alliance, the ethnic Tajik-led militia coalition that drove the Taliban from the north with U.S. help last fall and whose leaders now hold several key posts in the interim government. But he has made only grudging nods toward the new central authority. After vowing to boycott it, then backing off and attending Karzai's inauguration in December, Dostum was rewarded with the title of deputy defense minister. But he has not been seen in Kabul since, and plays no discernible role in the interim administration.

Keram, one of interim Defense Minister Mohammed Fahim's closest aides, returned three days ago from a mission to Mazar-e Sharif, where he said he confronted Dostum's lieutenants about the reported aid from Iran. They denied it, Keram said; Dostum was in India at the time.

But Keram said the Iranian aid was obvious and that he has documents to prove it, though he did not produce them for inspection. "They are giving two kinds of help to Dostum: They are giving money and they are buying weapons," he said. "Our intelligence sources are telling us how they are doing this. . . . They are giving General Dostum as much as he needs for his military."

Iran has been eager to regain some sway in Afghanistan after years of being shut out by the Taliban, and was the first nation to reopen its diplomatic mission in Kabul after the Northern Alliance captured the capital in November. It has promised $560 million in reconstruction aid over the next five years, and today it threatened to expel former Afghan guerrilla leader Gulbuddin Hekmatyar after he called for an armed struggle against foreign troops operating in Afghanistan with the interim government's blessing.

A top Iranian official here disputed reports of providing material support to Dostum or Khan. "Of course it's wrong," said Mohammed Reza Bahrami, the Iranian Embassy's interim charge{acute} d'affaires. "We focus our activities through the interim government. We accept the government and support it. There is no special relationship with Ismail Khan or Dostum or the other regions."

Other diplomatic sources suggested the assistance could be coming from Iran's religious establishment, which controls the most powerful ministries in the government. Iranian President Mohammad Khatami, a reformer, has pledged to respect Afghanistan's national integrity, but a high-ranking Afghan intelligence official, who asked not to be identified, said he believed aid for Dostum could be coming from forces allied with Iran's supreme religious leader, Ayatollah Ali Khamenei.

In an interview this week, Karzai said he had spoken with Khatami by telephone and planned to visit him soon. Asked if Iran had been interfering in Afghan affairs, Karzai paused before answering: "So far they've been nice. They've given us help, salaries for ministries. But we are very determined to protect our national sovereignty and our territorial integrity."

Other members of Karzai's government, however, see any Iranian ties to Dostum or Khan as a threat. Agriculture Minister Seyyed Hussein Anwari, who has been close to Iran for years, warned Tehran against interfering.

"Foreign relations must be established by the Ministry of Foreign Affairs," Anwari said in an interview. "The commanders don't have a right to have an independent relationship with other countries."

In recent weeks, Dostum's militia has been skirmishing around Mazar-e Sharif with the forces of two rival faction leaders, Attah Mohammad and Mohammad Mohaqiq -- both of whom also were key commanders in the Northern Alliance's fight against the Taliban. A truce negotiated this week commits the combatants to withdraw their troops from Mazar-e Sharif and other northern cities, to be replaced by government-backed security forces.

Afghan officials in Kabul said the recent fighting represented the beginning of a drive by Dostum to expand his base across the north.

"General Fahim has told him many times not to continue hostilities among the people of Afghanistan," the Afghan intelligence official said. "Right now, we see he hasn't accepted what the defense minister told him. . . . He's trying to buy commanders, and he's trying to extend the areas under his control."

The official said that the interim government has considered dispatching another ethnic Uzbek commander, Abdul Malik Pahlawan, to deal with Dostum. Malik, once Dostum's second-in-command, betrayed him to the Taliban in 1997, setting off a string of massacres as Mazar-e Sharif changed hands twice.

Malik "has the ability to defeat Dostum, but we don't want to start fighting again," the intelligence official said. "We're keeping quiet and we're waiting to see what happens."