At least 22 militants were killed and several injured when the Pakistani army launched air strikes in the country's northwest tribal area of Shawal, local media reported on Saturday.Troops backed by fighter jets pounded several hideouts of suspected militants in Shawal, a town located in the restive North Waziristan tribal area along the Pakistan-Afghanistan border, Dawn quoted an Inter-Services Public Relations statement.Saturday's air strikes were a continuation of the ongoing operation Zarb-e-Azb in North Waziristan which has so far killed over 3,000 militants.According to an earlier statement by the director general of Inter-Services Public Relation, the army's media wing, the operation in Shawal town was the last push against militants as the nearly 17-month long offensive has entered its final phase as most of the areas in North Waziristan have been cleared of militants.