Adopting a resolution by an overwhelming majority, the 127-member North West Frontier Province assembly said Musharraf should resign if he fails to take a confidence vote or else the 65-year-old former general should be impeached.
A similar resolution was passed by the powerful Punjab Provincial Assembly on Monday. The Assemblies of Sindh and Balochistan are expected to approve similar resolutions in coming days.
The impeachment motion against Musharraf will be submitted in parliament next week, Pakistan's ruling coalition said on Tuesday adding its own voice to the quit demand. Otherwise, it said, the president has to face the "tidal wave" of opposition.
"When the day comes next week, when we move our resolution for the joint (sitting of the National Assembly and Senate), we will have much more (votes) than we need (to impeach the President)," Pakistan People's Party leader and Information Minister Sherry Rehman told reporters.
