Nawaz Sharif was sentenced in absentia last week to 10 years in prison by a corruption court.
A local leader of the Awami National Party (ANP), Haroon Bilour, was among those killed in the attack in the city of Peshawar late on Tuesday.
Pakistan will deploy 371,388 troops to polling stations across the country to ensure free and fair elections on July 25, the army said Tuesday.
The three-time former prime minister and his daughter are currently in London.
The anti-graft court ruled that the Sharif family bought properties in London with the money plundered from Pakistan in the 1990s.
A suicide bombing Sunday targeting a warehouse in Kirkuk where ballot boxes from Iraq's May elections were stored wounded 19 people, days before a vote recount, a security source said.
Pakistan's top court on Thursday banned another loyalist of former prime minister Nawaz Sharif from politics for five years, in a decision that raised questions about the credibility of national elections next month.
The state of emergency has been in place since after an attempted coup in July 2016 and has been extended every three months since then.
US pro-democracy groups have urged Zimbabwean authorities to take steps to ensure a free and fair election in July and break from a history of flawed elections under long-time ruler Robert Mugabe.
Australia has established a security task force to guard against cyber attacks and interference in elections, the government said on Saturday, amid concerns foreign powers are meddling in domestic affairs ...
Right-wing nationalist Orban, who was re-elected with a landslide in April elections for a third straight term, did not reveal any further details.