The Baloch Liberation Army (BLA), which claimed a deadly attack on Chinese citizens in Karachi on Tuesday, is the most prominent of a number of separatist groups operating against the Pakistani state in the southwestern province of Balochistan.
BLA's stated aim is complete independence for Balochistan, Pakistan's largest province by territory but the smallest in terms of population given its arid mountainous terrain.
The province has seen a decades-long insurgency against what separatists call the unfair exploitation of resources in the mineral-rich region.
Balochistan borders Afghanistan to the north, Iran to the west and has a long coastline on the Arabian Sea. It has Pakistan's largest natural gas field and is believed to have many more undiscovered reserves.
It is also rich in precious metals including gold, the production of which has grown over recent years.
Most of the separatist groups operate independently, but some recent reports in local media have pointed to increasing cooperation between them.
Pakistani security forces have been their main focus, but in recent years they have also targeted Chinese interests, given Beijing's increasing economic footprint in the region.
Among China's major projects in Balochistan is the port of Gwadar, strategically located near the Strait of Hormuz - a crucial oil shipping route in the Arabian Sea. Chinese engineers working at the port came under attack from an operation claimed by the BLA last year.
A Chinese company also operates a major gold and copper mine in Balochistan.
The security of its nationals in Pakistan has become a major issue for Beijing, especially since it launched the China-Pakistan Economic Corridor (CPEC), which envisages development projects worth more than $60 billion.
The BLA says it attacks Chinese nationals because Beijing ignored warnings not to enter deals and agreements regarding Balochistan before the province had been "liberated". Reuters has not been able to verify its claims independently.
The group demands that all Pakistani security forces withdraw from Balochistan and has suggested negotiations in the presence of an "international guarantor".
It claims its "Fidayees" (guerrillas) are made up of young, educated Baloch who are disillusioned by hardship and being sidelined from economic development.
Under its current guise, the BLA was led by Balach Marri, scion of an influential Baloch family. Security officials said Marri was killed in neighbouring Afghanistan in 2007, where he had established a base and hideout.
After initially being hampered by Marri's death, the BLA has accelerated its attacks, particularly in the last year.
The group says it is currently led by a man named Bashir Zeb Baloch, the organisation's shadowy commander-in-chief about whom little is known.
The BLA has claimed a number of major attacks in recent months, including a simultaneous storming of two paramilitary bases in Balochistan earlier this year.
Most of the attacks take place in Balochistan or in the southern city of Karachi, Pakistan's commercial hub located close to the province.
The BLA claimed attacks there on the Pakistan Stock Exchange Building in 2020 and the Chinese consulate in 2018.
(Reporting by Gibran Peshimam; Editing by Alexandra Hudson)
