ISLAMABAD, July 23 (Xinhua) -- At least 25 people have been injured in a hand grenade attack at an office of a political party in Pakistan's southwest district of Chaghi, local media reported Monday.

According to the reports, some unknown miscreants on Sunday night lobbed a hand grenade at the people sitting in the election campaign office of the Balochistan Awami Party (BAP) in Dalbandin town of Chaghi, a district in the country's southwest Balochistan province.

Police, security forces and rescue teams rushed to the site and shifted the injured to hospital, where around five of the wounded were reportedly to be in critical condition.

Security forces have cordoned off the area and launched a search operation.

No group has claimed the attack yet.

It is the second terrorist attack on Sunday at the people campaigning for the country's general elections to be held on July 25. Earlier in the day, a suicide bomb attack killed a candidate for a provincial assembly seat of northwest Khyber Pakhtunkhwa province.

Since the start of July, it was the ninth terrorist attack on election candidates. At least 170 people including three prominent politicians have been killed and over 200 others injured in terrorist attacks at public rallies across the country during the last three weeks. Enditem