No group has claimed responsibility for the two attacks since Thursday, which police said they were investigating.

"Customs officials were present for checks... when unknown persons opened fire," said the district deputy superintendent of police, Muhammad Adnan, adding that two people were injured and the area on a busy highway had been cordoned off.

"Three days ago, five officials, including an officer, of the customs department, were killed in a shooting in the same area and the attackers escaped," he said.