Pakistan's ousted prime minister Nawaz Sharif was last night arrested at an airport and ferried immediately to jail after returning home to face prison for corruption, as the country's election campaign descended into violence.

The figurehead of Pakistan's ruling party was held and taken to a waiting plane to be flown to Islamabad soon after touching down in his Lahore stronghold with an entourage of aides and reporters.

His arrest came after a sweeping security crackdown devised to prevent supporters from greeting him in a show of strength.

However, hours before Sharif arrived with his daughter Maryam, who was also arrested, an Islamic State of Iraq and the Levant (Isil) suicide bomber killed at least 128 people at an election rally in Baluchistan province.

The blast, the deadliest attack in Pakistan since 2014, in Mastung was the third election bomb attack this week and followed the killing of four at a Friday rally in Bannu.

The campaign also saw the ex-wife of Imran Khan publish a tell-all memoir less than two weeks before polling.