(CNN)-- Iran's official news agency reported early Saturday, citing the Revolutionary Guard, that two oil tankers exploded and caught fire after attempting to cross a mined path in the Strait of Hormuz.

In a statement, the Guard described the waterway as 'extremely unsafe and completely closed.'

Six ships crossed the Strait of Hormuz in the past 24 hours according to MarineTraffic data, reflecting the increasing pressures faced by vessels in one of the world's busiest maritime chokepoints.

These included a tanker and two cargo ships leaving the strait, and two tankers and a cargo ship entering it; these numbers align with transit rates recorded in the past few days, which have seen a decline.

US President Donald Trump earlier this month announced a plan to impose a 20% fee on all cargo shipments passing through this waterway, adding further burden on shipping traffic in the region.

Since the outbreak of the war, the strait has also seen an increase in GPS signal spoofing - a form of navigation system jamming that makes ships appear at incorrect coordinates - although this phenomenon had subsided before the collapse of negotiations between the United States and Iran earlier this month.