Who are the Pakistani Baloch separatist militants behind train hijacking?

Separatist militant group the Baloch Liberation Army (BLA) claimed that they had taken hostages during an attack on a train carrying hundreds of people, including paramilitary troops, in southwestern Pakistan on Tuesday and threatened to kill them.

The BLA is the strongest of a number of insurgent groups long operating in the area bordering Afghanistan and Iran, a mineral-rich region that is home to Beijing's investment in Gwadar deep water port and other projects.

In what was previously a low-level insurgency, the militants have in recent months stepped up their activities using new tactics to inflict high death and injury tolls and target Pakistan's military.

Here are facts about the group, which has also targeted Chinese interests.

WHAT ARE THE BLA'S GOALS?

The BLA seeks independence for Balochistan, a province located in Pakistan's southwest and bordering Afghanistan to the north and Iran to the west.

It is the biggest of several ethnic insurgent groups that have battled the federal government for decades, saying it unfairly exploits Balochistan's rich gas and mineral resources.

The insurgents have been fighting to lay a claim to local resources which they say belong to their people.

Balochistan's mountainous border region serves as a safe haven and training ground for the Baloch insurgents and Islamist militants.

HOW HAS IT BECOME MORE LETHAL?

The BLA shocked the country's security establishment when it stormed army and navy bases in 2022.

It has deployed women suicide bombers, including in an attack on Chinese nationals at a university in Karachi and a bombing in southwest Balochistan.

An umbrella group of several Baloch ethnic groups said last week that it had convenedall factions in a bid to unite them under a unified military structure.

A dormant BLA splinter group called BLA (AZAD) became active in recent weeks.

WHAT ARE THE BLA'S TARGETS?

The BLA often targets infrastructure and security forces in Balochistan, but has also truck in other areas - most notably the southern port city of Karachi.

The insurgents target Pakistan's army and Chinese interests, in particular the strategic port of Gwadar on the Arabian Sea, accusing Beijing of helping Islamabad to exploit the province.

Militants have killed Chinese citizens working in the region and attacked Beijing's consulate in Karachi.

The BLA, separately, was also at the centre of tit-for-tat strikes last year between Iran and Pakistan over what they called militant bases on each other's territory, which brought the neighbours close to war.

BALOCHISTAN'S SIGNIFICANCE

Balochistan is an important part of China's $65 billion investment in the China Pakistan Economic Corridor, a wing of President Xi Jinping's Belt and Road initiative.

It is home to key mining projects, including Reko Diq, run by mining giant Barrick Gold (ABX.TO), and believed to be one of the world's largest gold and copper mines.

China also operates a gold and copper mine in the province.

The decades-old insurgency has continued to keep the province of some 15 million people unstable and created security concerns around Pakistan's plans to access untapped resources.

It is Pakistan's largest province by area, but smallest by population. Balochistan also has a long Arabian Sea coastline, not far from the Gulf's Strait of Hormuz oil shipping lane.

Hundreds of Baloch activists, many of them women, have protested in Islamabad and Balochistan over alleged abuses by security forces - accusations the government denies.

Islamabad accuses India and Afghanistan of backing the militants to damage Pakistan's relations with China, a charge both countries deny.