JACKSON, Miss. - Mississippi lawmakers are advancing a proposal to add firing squad, electrocution and gas chamber as execution methods in case a court blocks the use of lethal injection drugs.

Republican Rep. Andy Gipson says House Bill 638 is a response to lawsuits by "liberal, left-wing radicals."

The bill passed the House amid opposition Wednesday, and moves to the Senate.

Lethal injection is Mississippi's only execution method. The state faces lawsuits claiming the drugs it plans to use would violate constitutional prohibitions against cruel and unusual punishment.

Mississippi hasn't been able to acquire the execution drugs it once used, and it last carried out an execution in 2012.

The Death Penalty Information Center says of the 33 states with the death penalty, only Oklahoma and Utah have firing squad as an option.