Quetta: At least four people were injured after unidentified motorcyclists hurled a hand grenade on the Sariab Road of Pakistan's Quetta at a security check post on Saturday night, a local media report said.

The police official said that four civilians, who were walking on the side of the road when the attack took place, were injured and two of them were taken to the hospital, Dawn reported.

"We have received four injured in the trauma centre," said Dr Wasim Baig, a hospital doctor.

Security forces cordoned off the area and launched a search operation and took some suspects for interrogation.

No organisation has claimed responsibility for the attack, reported Dawn.

Earlier, on October 7, three people were injured after unidentified attackers hurled a hand grenade in the Hayatabad suburb of Pakistan.

The incident took place in Phase-1, Hayatabad where unidentified attackers threw a grenade into a house and the subsequent explosion wounded three people who were later rushed to a nearby hospital, Dawn reported.

Hayatabad, where the explosion took place is a suburb on the western outskirts of Peshawar, the capital of the Khyber Pakhtunkhwa province of Pakistan.

According to Dawn, a house in the same township had been attacked with a grenade a few days ago, injuring one person.

Meanwhile, one person was injured in a cylinder blast in the Industrial Estate of Hayatabad Friday evening.

The highest number of terror incidents in Pakistan this year was recorded in September, said an Islamabad-based think tank, as it pointed to the resumption of attacks by the outlawed Tehrik-i-Taliban Pakistan (TTP).

The number of terror attacks increased in September compared to August this year, the Dawn newspaper reported citing the Pakistan Institute for Conflict and Security Studies (PICSS).

September witnessed 42 militant attacks with an increase of 35 per cent compared to August. The Pakistani think tank also observed an increase of 106 per cent in violence in erstwhile FATA and Khyber Pakhtunkhwa (KP).

In August this year, the think tank said the militants carried out 31 attacks across Pakistan, where 37 people were killed and 55 others injured.

"Peace negotiations with the TTP remained in limbo during the month but due to fear of target killing, the top leadership of the group, including its head Mufti Noor Wali, went into hiding. A series of target killing incidents happened in August in which some senior TTP commanders were killed in Afghanistan," PICSS was quoted as saying by Dawn.

Global security agencies say there's a high threat of terrorism and sectarian violence throughout the country.