A ROADSIDE bomb exploded near a vehicle carrying security forces in restive north-west Pakistan, killing four police officers and wounding five others, officials said today.

The deadly attack came the same day two schoolchildren were killed when a mortar exploded near them elsewhere in the north-west.

The roadside bombing happened on Wednesday in South Waziristan district, a former stronghold of the Pakistani Taliban, local police officer Dilawar Khan said.