According to Pakistani officials, the death toll from a suicide bombing at a religious party’s electoral event on Monday has grown to 45.
The incident heightens tensions ahead of a national election later this year.
On Sunday in the northwest, near the Afghan border, a bomber struck a gathering of the conservative Jamiat Ulema Islam-Fazl (JUI-F) party, which is associated with the government and renowned for its links to radical Islamists.
However, no organization has claimed responsibility.
Bilal Faizi, a state-run rescue agency spokesman, claimed the death toll had grown to 45. Riaz Anwar, the government’s health adviser, reported that 61 of the more than 130 injured persons were being treated.
According to authorities, a counter-terrorism unit examining the blast believes the Islamic State organization was behind it.
Since last year, when a truce between the Pakistani Taliban, the Tehreek-e-Taliban Pakistan (TTP), and the government fell apart, Pakistan has experienced a revival of attacks by Islamist militants.
In January, a mosque bombing in the northwest city of Peshawar killed more than 100 people, but assaults against political parties are uncommon.
While the TTP and allied factions have been behind the majority of recent strikes, a spokesman for the organisation condemned the attack on Sunday.
The JUI-F is an ally of Prime Minister Shehbaz Sharif’s coalition administration, which condemned the blast as an attack on the democratic process.
The prospects for the November general election have already been muddied by months of conflict between major parties and claims of military meddling in civilian affairs. The military disputes this.