A key U.S. official says Washington has evidence linking the Pakistani government to a militant group blamed for a series of attacks in Afghanistan.

U.S. Ambassador to Pakistan Cameron Munter tells Radio Pakistan there are apparent ties between Islamabad and the Haqqani network. Munter also said those ties must be severed.

The United States has suspected Pakistan's intelligence agency has ties to the Haqqani network and other militant groups in Afghanistan but rarely says so publicly.

The U.S. and NATO have blamed the Haqqani network for attacks on U.S. and NATO troops and on U.S. targets, including the September 13 strike against the U.S. embassy in Kabul.

The Associated Press said Saturday Pakistani officials have not responded to Munter's comments.