WASHINGTON (Reuters) - Pakistan's use of violent intimidation to quell political protests threatens U.S. and Pakistani interests, and President Pervez Musharraf must be encouraged to restore democratic processes, several U.S. congressmen say.

The unusually blunt comments to Secretary of State Condoleezza Rice by Sen. Joseph Biden and Rep. Tom Lantos, both Democrats, and Republican Rep. Ileana Ros-Lehtinen reflect growing U.S. unease with Musharraf's handling of a widening confrontation with political foes and prospects for Pakistan's stability.

..........

They said a violent confrontation in Karachi on May 9 that left at least 39 people dead and 150 wounded showed "disturbing signs of collusion between MQM and government forces."

MQM, or Muttahida Quami Movement, is a coalition partner of Musharraf's party in the government.

"The paramilitary Rangers and police, whether by inaction or acting on specific orders, clearly failed to protect the lives of citizens under attack by armed gangs," the lawmakers wrote.