At least five people were killed and five others injured when a blast went off near a political rally in Pakistan's southwest Balochistan province on Tuesday, official sources said.

The incident happened around 5:35 p.m. local time (1235 GMT) when explosive materials fixed at a motorbike exploded in Sibi district of the province, the sources told Xinhua.

The rally of Pakistan Tehreek-e-Insaf (PTI) was targeted in the attack, the sources added.

The injured people were shifted to a nearby hospital where three of them are in critical condition, the officials said, adding that the area was cordoned off for investigations. No group has claimed the attack yet.