QUETTA: Armed militants on Wednesday torched a container carrying Nato equipment in the Western Bypass area of Quetta, the capital of volatile Balochistan province, police said.

A police official who requested anonymity told Dawn.com that the gunmen opened fire at the Nato container which was on its way from Kandahar to Port Qasim in Karachi.

He said the militants torched the container. However, the driver and cleaner managed to escape unhurt from the spot. He said the militants sped away on their motorcycles after the incident.

In a separate incident, armed militants opened fire at a polio team in the province’s Sibi district.

Muhammad Aslam, a police official, told Dawn.com that militants opened fire at the team of polio vaccination workers in Bukhari Muhalla area of Sibi. He said there was no human loss as police were quick to reach at the spot.

Nonetheless, no arrests were carried as the militants escaped from the spot.

The polio vaccination campaign has been underway for the last three days in Quetta and other districts of Balochistan. Wednesday was the final day for the polio drive.

There was no immediate claim of responsibility for either of the attacks.

The attack came as a bomb killed seven policemen on their way for security duty for polio immunisation workers in neighbouring Khyber Pakhtunkhwa province’s Charsadda district.

Wednesday’s attacks come only a day after the immunisation drive in Karachi was suspended following the attack on a vaccination team in the city's Qayyumabad area.

The spike in attacks on polio worker teams across comes just days after the World Health Organisation warned that Pakistan's northwestern city of Peshawar was the world's “largest reservoir” of the polio virus.

Militant groups see vaccination campaigns as a cover for espionage, and there are also long running rumours about polio drops causing infertility.

According to the World Health Organisation, Pakistan recorded 91 cases of polio last year compared with 58 in 2012. So far, four new polio cases have been recorded in 2014.