The death toll from a suicide bombing at a political rally in Pakistan has risen to 54, officials confirmed on Monday. The attack took place in the Bajaur district on Sunday during a gathering of the conservative Jamiat Ulema Islam-Fazl (JUI-F) party, which is allied with the government and known for its links to hardline Islamists. No group has claimed responsibility for the attack. Counter-terrorism officers investigating the blast suspect that the Islamic State group may be behind it. The attack has raised concerns about security ahead of the general election later this year. Pakistan has witnessed a surge in attacks by Islamist militants since the breakdown of a ceasefire between the Pakistani Taliban, known as the Tehreek-e-Taliban Pakistan (TTP), and the government last year. While the TTP has been responsible for most of the recent attacks, the group distanced itself from Sunday's attack. The JUI-F is an ally of the coalition government of Prime Minister Shehbaz Sharif, who condemned the blast as an attack on the democratic process. The military denies any involvement in civilian politics. Funerals for the victims took place on Monday, with mourners expressing grief and demanding justice. The government has promised to identify and punish those responsible for the attack.