Kabul, Afghanistan ? Defense Secretary Robert Gates said Monday that Iranian weapons are falling into the hands of anti-government Taliban fighters but he stopped short of blaming Tehran. Afghan President Hamid Karzai seemed to dismiss the matter.

At a news conference at the presidential palace, Gates offered possible explanations for the flow of weapons from Iran to this war-scarred country, including smuggling. He mentioned no specific weapons, but NATO officials recently cited the discovery in Kabul of an armor-piercing roadside bomb, the same type U.S. officials have long complained are entering Iraq from Iran.

“There have been indications over the past few months of weapons coming in from Iran,” Gates told reporters with Karzai at his side. “We do not have any information about whether the government of Iran is supporting this, is behind it, or whether it’s smuggling.”

Gates, on his second visit to Afghanistan since becoming Pentagon chief last December, said that while the weapons appear to be going to Taliban fighters, some may be headed to criminals in the Afghan drug trade. Asked his own view, Karzai appeared eager to give the Iranian government a pass.

He said there was no evidence of Iranian government involvement, adding, “Iran and Afghanistan have never been as friendly as they are today.”

There is no reason for Iran to aid the Taliban, Karzai said. “It is in the interests of our brothers in Iran” to support the development of a more stable and prosperous Afghanistan. He said that also applied to Pakistan, on Afghanistan’s eastern border, where U.S. officials say Taliban fighters have found haven and easy passage for cross-border attacks on U.S., NATO and Afghan troops.

A prevalent view among U.S. officials is that Tehran, while not an ally of the Taliban, is seizing any feasible opportunity in both Iraq and Afghanistan to complicate U.S. stabilization efforts and to tie down the American military amid tensions between Tehran and Washington over Iran’s nuclear program.