Pakistani officials say a female suicide bomber has killed herself and another woman near a police check post in the northwest city of Peshawar.

Officials say the woman threw a grenade at police before detonating her explosives-laden vest, just meters away from where a roadside bomb attack killed four police officers and a child just moments earlier on Thursday.

At least 14 people were wounded in the first attack, when a remote-control roadside bomb in a hand cart targeted a police vehicle near the Lahori Gate area of the city. At least three people were wounded in the second attack.

Police say they are investigating whether the woman killed in the suicide bomb attack was an accomplice or a bystander. No group has claimed responsibility for the attack.

Attacks by female suicide bombers are rare in Pakistan.

Peshawar, which lies near the country's restive border with Afghanistan, has experienced numerous Taliban and al-Qaida linked suicide attacks and bomb explosions in recent years.