More than 20 armed men crossed the border from Iran into Afghanistan and entered a town, a police commander said in the first such blunt claim by a high-ranking Afghan official.
Colonel Rahmatullah Safi - police commander in the three western provinces of Farah, Badghis and Herat - said according to intelligence information, the group of armed militants crossed the border on Monday in Farah's Anardara district.
"Two pickup trucks with over 20 armed people riding in them crossed the border from Iran to Afghanistan," Safi said in his Border Police headquarters, 15 km outside Herat city.
He said according to intelligence information, the men were heading towards Zirkoh area in Farah province, which has been the site of escalating militant activity in recent months.
Safi said the police did not have the opportunity to track down the vehicles but said he had informed President Hamid Karzai and international forces in the country.
"I can say with certainty that the vehicles came from Iranian soil, and if they came from Iran with ammunitions and explosives, of course, they are supported by the Iranian government. If the Iranian border forces really want to stop them, they can," he added. "They have one outpost every five to 10 km."
Safi's report of the infiltration comes at a time when US officials have linked Iran's government to large shipments of weaponry to militants in Afghanistan, but Karzai and other Afghan officials have ruled out Iran's involvement and Tehran has also strongly denied funnelling weapons to Afghan militants.
Safi also revealed that during fighting Saturday night between Afghan police and insurgents in the Shindand district of Herat province, which left nine suspected Taliban and two police officers dead, police found the remains of Iranian-made bullets.
He also showed DPA five anti-tank mines that had Iranian markings, which he said were seized at the Afghan-Iran border about two weeks ago.
Safi said his police forces had information that former mujahideen fighters, who forced Soviet forces from Afghanistan and later plunged the country into a bloody civil war, were receiving training in Iranian territory and were sent back to Afghanistan to carry out attacks against the government and international forces.
In April, US officials said Iranian-made weapons had showed up in the hands of the Taliban. The Pentagon's top general, Peter Pace, said NATO forces in Afghanistan had seized Iranian-made mortars and explosives destined for the Taliban.
Last week, a top US State Department official charged in a CNN interview that the US has "irrefutable evidence" that Iran is arming Taliban fighters in Afghanistan.
Although not mimicking the strong nature of Undersecretary of State Nicholas Burns' remarks, US Defence Secretary Robert Gates said a day later that large weapons' shipments were crossing from Iran into Afghanistan and it was unlikely Tehran did not know about them.
"Given the quantities that we're seeing, it is difficult to believe that it is associated with smuggling or the drug business or that it's taking place without the knowledge of the Iranian government," Gates said.
Afghan Defence Minister Abdul Rahim Wardak, however, rejected Iran's involvement in supplying militants in a media interview, arguing that Kabul and Tehran have good relations and a stable Afghanistan is in Iran's interest. He said there was evidence weapons were coming from Iran but suggested they were from the Al Qaeda terrorist network or drug traffickers.
Gates also mentioned the good relations between the Afghan and Iranian government. "Whether Iran is trying to play both sides of the street, hedge their bets, what their motives are, other than causing trouble for us, I don't know," the US defence chief said.