At least 25 killed in strikes as peace talks break down.
Dozens injured in latest violence during gov't-Taliban peace talks.
Kareem Khan was due to testify about the impact of strikes on Pakistan.
Explosions cut gas supply to country's most populous province.
The two sides are due to start charting a "roadmap" for peace talks.
Gov't cancelled preliminary peace talks scheduled to start Tuesday.
Briton of Pakistani origin had written letters claiming to be a prophet.
Bomb targeting polio security team killed six policemen and a boy.
Attack in Karachi comes day after start of new vaccination drive.
Airstrikes come amid calls for tougher action against Taliban fighters.