Separatist militant attacks on police stations, railway lines and highways in Pakistan's restive province of Balochistan, coupled with retaliatory operations by security forces, killed at least 51 people, officials said on Monday, Paralel.Az reports citing Reuters.

"These attacks are a well thought out plan to create anarchy in Pakistan," Interior Minister Mohsin Naqvi said in a statement, adding that security forces had killed 12 militants in operations after the attacks, but without giving details.

The largest of the attacks targeted vehicles from buses to goods trucks on a major highway, killing at least 23 people, officials said, with 35 vehicles set ablaze.

Rail traffic with Quetta was suspended following blasts on a rail bridge linking the provincial capital to the rest of Pakistan, as well as on a rail link to neighbouring Iran, railways official Muhammad Kashif said.

Police said they had found six as yet unidentified bodies near the site of the attack on the railway bridge.

Officials said militants also targeted police and security stations in Balochistan, which is Pakistan's largest province, killing at least 10 people in one attack.

Militant group the Baloch Liberation Army (BLA) took responsibility in a statement to journalists that claimed many more attacks, including one on a major paramilitary base, though Pakistani authorities have yet to confirm these.

The BLA is the biggest of several ethnic insurgent groups that have battled the central government for decades, saying it unfairly exploits Balochistan's gas and mineral resources. It seeks the expulsion of China and independence for the province.

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A militant attack on a highway in southwestern Pakistan targeted vehicles from buses to goods trucks, killing at least 23 people, officials said on Monday, with ten vehicles set ablaze, Paralel.Az reports.

Armed men blocked the route in the restive province of Balochistan on Sunday night, took passengers off the vehicles, and shot them after checking their identity cards, a senior superintendent of police, Ayub Achakzai, told Reuters.

In a statement, Interior Minister Mohsin Naqvi said 23 people had been killed, although Achakzai had put the toll at 22.

"The armed men also not only killed passengers but also killed the drivers of trucks carrying coal," said Hameed Zahir, the deputy commissioner of the area where the incident occurred.

At least 10 trucks were set on fire after their drivers had been killed, he added.

Militants fighting a decades-old ethnic insurgency to demand the secession of resource-rich Balochistan from Pakistan have targeted workers from the eastern province of Punjab whom they see as exploiting their resources.

In a statement, the Balochistan Liberation Army group said its fighters had targeted military personnel traveling in civilian clothes, who were shot after being identified.

Pakistan's interior ministry said the dead were innocent citizens, however.

The office of Prime Minister Shehbaz Sharif condemned the attack in a statement, vowing that security forces would retaliate and bring those responsible to justice.