The United States has added the Communist Party of Nepal-Maoist to its list of terrorist organizations, a move which mandates a freeze on the group's assets.

The announcement by the State Department Friday follows last week's threat by Maoist rebels to target U.S.-backed organizations in Nepal.

A later statement by a Maoist rebel leader promised his forces will not attack Americans unless they are directly involved with Nepalese military operations. The rebels have criticized Washington for giving Kathmandu millions of dollars in military and development aid, and for helping to train Nepalese soldiers.

By declaring the Communist Party of Nepal a terrorist group, U.S. officials have cleared the way to freeze any assets it may have in the United States. Washington can also ask United Nations members to take similar action.

Maoist violence has surged in Nepal since August, when the rebels left peace talks and broke a cease-fire. The Maoists have been fighting since 1996 to replace the Nepalese monarchy with a communist state.