Train services on both up and down tracks in all affected cities were suspended immediately after the explosions. –Photo by APP (file photo)

KARACHI: Suspected militants blew up railway tracks at four sites in Pakistan's southern province of Sindh early Friday, disrupting train services, officials said.

Two people were injured when two small bombs damaged the tracks near the Baloch Colony bridge area in Karachi, DawnNews reported. However, no casualties were reported in the explosions in Hyderabad, Nawabshah and Mehrabpur districts.

The explosions appeared to be coordinated attacks, police and railway officials said.

“Two low-intensity bombs planted on both the up and down railway tracks went off outside Karachi early morning, causing damage to the tracks,” senior police officer Chaudhry Asad told AFP.

Train services were suspended and repair work had begun, he said.

About 30 minutes later two more blasts damaged railway tracks near near the Hussainabad area in Hyderabad, Pakistan Railways official Aftab Memon said.

Two additional blasts on tracks were reported from Nawabshah, between the Nawaz Dahri and Sarhari Railway stations and another two in the Sindh area of Mehrabpur, he said.

“All these blasts were similar in nature, causing damage to the track,” he said.

Home ministry official Sharfuddin Memon blamed militants for the attacks, AFP reports.

“These attacks are linked to the situation in northwest Pakistan and the aim was to target communications networks and create panic among the people,” he said.

Pakistan suffers near-daily attacks blamed on Taliban and al Qaeda-linked militants, who are most active in the lawless tribal belt of northwest Pakistan on the border with Afghanistan.

A teenage suicide bomber killed up to 31 Pakistani army recruits at a parade ground on Thursday, an attack the Taliban said was revenge for US drone strikes and local military offensives.

However, attacks by the extremists on infrastructure such as railways are relatively rare.