As the Strait of Hormuz at its narrowest is wide, in order to traverse the strait, ships must stay within sea lanes that pass through the territorial waters of Iran and Oman under the transit passage provisions of customary Law of the Sea. It is therefore normal for ships, including warships, entering or leaving the Persian Gulf to transit Iranian territorial waters. During the Iran–Iraq War the Iranian forces frequently boarded and inspected neutral cargo ships in the Strait of Hormuz in search of contraband destined for Iraq. While legal under international law, these inspections added to the tensions in the area.