Three children were killed and another two injured in a hand grenade explosion in Killi Badezai area of Quetta on Thursday, police said.

The children, aged between 10 and 14 years, found the grenade at a graveyard, Javed Qamar, a senior police official, said.

It “exploded while they were playing with it”, he told AFP.

As a result, three of the children died on the spot, while two sustained injuries, a spokesperson for the provincial Counter-Terrorism Department (CTD) told Dawn.com.

Balochistan government spokesperson Liaquat Shahwani while citing the CTD report said the children were playing with the hand grenade "after mistaking it for a toy" when it exploded.

The bodies and injured were shifted to the Bolan Medical Complex Hospital. Qamar said the condition of the two wounded children was serious.

Security officials cordoned off the site as they launched an investigation into the explosion.

The incident comes 10 days after a blast on Quetta's Qambrani Road left five people injured.

Police said the explosion was caused by an improvised explosive device (IED) planted at the side of the road. One security official was also among the injured.

While condemning the blast, Balochistan Chief Minister Jam Kamal Khan Alyani had said at the time that "protection of the public's lives and properties is the responsibility of the government". He had also directed authorities to take steps for "foolproof security arrangements" for the protection of citizens' lives.

In April, a powerful bomb exploded in the parking lot of the Serena Hotel in Quetta, killing at least five people and wounding 12 others.