Islamabad- A suicide bomber attacked a security convoy on Wednesday in south-west Pakistan, killing a young girl and injuring 17 more, including 13 troops, a police official said.

The pedestrian bomber came across the road and blew himself up near a convoy of six to seven vehicles carrying paramilitary Frontier Corpse (FC) personnel in Quetta, the capital of the north-western province of Balochistan.

"Thirteen FC personnel and one passerby were injured while four schoolgirls were also wounded. One of the girls later on expired at the hospital," Asif Nawaz, Quetta police chief, told Geo news channel.

The attack came as authorities have put security at high alert following Saturday's truck suicide bombing at Islamabad's Marriott Hotel, where 53 people, including two US Marines and the Czech ambassador, died and more than 250 were injured.

Nawaz said the law enforcers had taken all necessary measures to ensure security but "it is not easy to stop a person who has already put his life at stake."

The western parts of Balochistan which border Afghanistan are centres of Taliban militant activities and some media reports have suggested that some senior leaders of the Afghan Taliban are hiding in Quetta. (dpa)