Iranian lawmakers plan to propose a bill to impose tariffs on ships sailing through the Strait of Hormuz according to Iranian MP Alireza Khosravi, Tehran based newspaper Shargh reported. Ships of certain countries transit the waterway at the mouth of the Persian Gulf “under pretexts such as security,” Khosravi said.

Nations whose oil tankers and other vessels exit or enter the Gulf must compensate for the environmental damage they cause there, he said. Khosravi didn’t identify specific countries or provide details of the draft bill, Shargh reported Monday.

Another parliamentarian, Mehdi Mousavinejad, said lawmakers may ask the legislative body to consider a proposal to restrict ship traffic in Hormuz, according to the state-run Fars news agency. They will review the measure when the parliament reconvenes after a summer break, Fars reported Monday. Lawmakers are scheduled to return to work on July 22.

The Strait of Hormuz between Iran and Oman is a transit point for about 20 percent of the world’s traded oil and 33 percent of the supply of liquefied natural gas. Some Iranian officials have threatened to disrupt shipping in response to economic sanctions imposed by the U.S. and EU, but Iran’s Foreign Ministry has said the country will do all it can to ensure safe shipment from the Gulf.