QUETTA, Pakistan (Reuters) - Gunmen have attacked a Pakistani security post in the resource-rich province of Baluchistan killing four paramilitary soldiers, officials said on Monday.

Separatists have for decades fought a low-level insurgency against the government in the southwestern province, which is seeing increasing investment in energy and infrastructure projects by China and others, including Saudi Arabia.

The Sunday attack in Panjgur district came as Saudi Arabia’s Crown Prince Mohammed bin Salman was arriving in Pakistan at the start of a tour of South Asia and China, which risks being overshadowed by escalating tension between nuclear-armed rivals India and Pakistan.

“The four men suffered multiple gunshot wounds and died on the spot,” Khan Wasay, a spokesman for the Frontier Corps paramilitary force, told Reuters.

No group claimed responsibility for the attack but it bore the hallmarks of the separatists who have long complained that Baluchistan’s gas and mineral resources are unfairly exploited by richer provinces, with little reward for the people of Pakistan’s poorest province.

Pakistan has accused old rival India of supporting the Baluchistan separatists. India rejects that.

China has funded development of a deepwater port at Gwadar in south Baluchistan, and is also investing in other projects as part of the giant China Pakistan Economic Corridor (CPEC).

Saudi Arabia is expected to announce this week eight investment agreements, including a $10 billion refinery and petrochemicals complex in Gwadar.