A suicide bombing that killed at least 45 people at a political rally in Pakistan on Sunday has again brought into focus the challenges in keeping militants at bay.

Pakistan has seen a resurgence of attacks by militants since last year when a ceasefire between the Tehreek-e-Taliban Pakistan (TTP) and Islamabad broke down.

Following are some details of Pakistan's tussle with hardline groups:

• Militants have mainly operated out of Pakistan's former tribal areas that border Afghanistan in the northwest. This region was known as the semi-autonomous Federally Administered Tribal Areas until a 2018 merger with neighbouring Khyber Pakhtunkhwa province.
• The region saw an influx of guerrilla fighters in the 1980s, and the Taliban and al Qaeda after the US-led campaign in Afghanistan began in 2001.
• The TTP, which has carried out some of the bloodiest attacks inside Pakistan since its formation in 2007, is an umbrella organisation of various hardline groups operating individually in Pakistan.
• Since the TTP is formed of several groups, some of which have splintered previously, it makes it difficult for Pakistani authorities to hold peace talks with them. The group has distanced itself from Sunday's attack and its spokesperson has condemned it.
• TTP attacks are mostly directed at Pakistan, unlike the other big militant threat in the region, Daesh.
• Daesh affiliate Islamic State in Khorasan (IS-K) bombed a Shi'ite mosque in Pakistan's Peshawar in 2022, killing scores of people.
• The group has been more active in Afghanistan than in Pakistan. There have been reported defections from the TTP into IS-K and some splinter cells have started to work closely together.
• A newly founded militant group called Tehreek-e-Jihad Pakistan (TJP) has also carried out a string of attacks in the country, most recently killing 12 soldiers at a Pakistani military base earlier this month.
• Little is known about the TJP and whether it operates under any larger militant group.
• Sunday's explosion took place in the former tribal area of Bajaur. The party targeted, the conservative Jamiat Ulema Islam-Fazl (JUI-F), is known for its links to hardline political Islam and is a major ally of the coalition government.
• The JUI-F and its chief Maulana Fazl-ur-Rehman were previously attacked because the party opposes local militants, saying their armed campaign against the state doesn't constitute a Jihad - a fight against opponents of Islam - analysts say.
• The party, however, supports the Afghan Taliban movement and calls it a just fight against foreign occupation.
• Militants like the TTP aim to overthrow the Pakistani government and install their own brand of strict Islamic law in the predominantly Muslim country of 220 million people.