Updated

Police say four people were killed and dozens were injured in two separate bombings of political targets in the southern city of Karachi.

The blasts come as Pakistan is preparing for country-wide elections on May 11.

There was no immediate claim of responsibility but the Taliban have threatened three political parties perceived as being more liberal and secular, including two targeted Saturday night.

Police officer Azam Baloch says three people were killed and 21 were injured when a bomb planted on a motorbike exploded during a political meeting. That blast targeted supporters of the Pakistan Peoples Party.

Police official Zahid Hussain says the other bomb targeted an office of the Muttahida Quami Movement. One person died and 21 were wounded in that explosion.