JAKARTA, Indonesia — The top American military officer said yesterday the discovery that roadside bombs in Iraq contained material made in Iran does not necessarily mean the Iranian government was involved in supplying insurgents.

The comments by the chairman of the Joint Chiefs of Staff, General Peter Pace, called into question assertions by three senior American military officials in Baghdad on Sunday who said the highest levels of Iranian government were responsible for arming Shiite militants in Iraq with the bombs, blamed for the deaths of more than 170 troops in the American-led coalition.

White House spokesman Tony Snow said Monday he was confident the weaponry was coming with the approval of the Iranian government. General Pace told reporters in the Indonesian capital, Jakarta, that American forces hunting militant networks in Iraq that produced roadside bombs had arrested Iranians and some of the materials used in the devices were made in Iran.

“That does not translate that the Iranian government per se, for sure, is directly involved in doing this,” General Pace said. “What it does say is that things made in Iran are being used in Iraq to kill coalition soldiers.”

On Monday, General Pace said he had no firm knowledge that the Iranian government had sanctioned the arming of the insurgents.

“It is clear that Iranians are involved, and it’s clear that materials from Iran are involved, but I would not say by what I know that the Iranian government clearly knows or is complicit,” General Pace told the Voice of America.

Iran denied it gave sophisticated weapons to militants to attack American forces.