Iran is preparing legislation that would impose tolls on ships passing through the Strait of Hormuz, according to Iranian state-aligned media.

Traffic in the waterway, a critical shipping route, has effectively come to a standstill since the U.S. and Israel’s war with Iran began almost four weeks ago. Subsequent supply constraints, along with attacks on energy facilities and regional production shutdowns, have pushed oil prices into triple digits.

Revolutionary Guard-aligned news agency Fars said overnight that a lawmaker had told its reporter the plans to impose tolls were also a bid to officialize Iranian supervision over the Strait of Hormuz.