The Maoists remain on Washington's blacklist of "specially designated global terrorists" even though they signed a peace deal with central government last November and declared an end to a decade-long insurgency.

The United States, however, argues that the ultra-leftists are still engaged in violence and have failed to properly disarm under the terms of the peace accord.

"As the US keeps us on a terrorist list, I asked him (Carter) to take our wish to be off the list to the US government, and he responded positively," said Prachanda, whose nom-de-guerre means "the fierce one."