A senior American diplomat said that there had not been any official contacts with the group and that he was unaware of its having received any support from the United States. He also said that Mr. Haj-Ahmadi, while in Washington, did not meet with administration officials.

Image The guerrillas send small teams into Iran, some of whom are armed with hand grenades and Russian-made machine guns. Credit... Warzer Jaff for The New York Times

Because the P.K.K. is on the State Department’s list of terrorist organizations and aiding such groups is illegal, the United States is eager to avoid any hint of cooperation with the P.J.A.K.

Guerrilla leaders said the Americans classify the P.K.K. as a terrorist group because it is fighting Turkey, an important American ally, while the P.J.A.K. is not labeled as such because it is fighting Iran.

In fact, the two groups appear to a large extent to be one and the same, and share the same goal: fighting campaigns to win new autonomy and rights for Kurds in Iran and Turkey. They share leadership, logistics and allegiance to Abdullah Ocalan, the P.K.K. leader imprisoned in Turkey.

While most Kurds are Sunni Muslims, the guerrillas reject Islamic fundamentalism. Instead, they trace their roots to a Marxist past. They still espouse what they call “scientific socialism” and promote women’s rights.

After skirmishes between the guerrillas and Iranian forces intensified this year, the Iranian military began shelling border villages in August, sending residents fleeing and killing livestock. The shelling drew angry criticism from Iraqi leaders, who condemned it as a disproportionate response.

But interviews with guerrillas suggest that they have inflicted considerable damage on Iran. While it is impossible to verify the claims, the leader of the P.K.K., Murat Karayilan, said the P.J.A.K. fighters had killed at least 150 Iranian soldiers and officials in Iran since August. And Biryar Gabar says 108 Iranians were killed in August alone.