Confusion in Strait of Hormuz amid reports Iran has reclosed the waterway

Tensions are building once again in the Strait of Hormuz amid reports that Iran has reclosed the waterway, potentially throwing the recently signed US-Iran memorandum of understanding into doubt.

In a post on Telegram on Friday, Iranian activist Ilia Hashemi said there were reports of warning shots fired in the area and that ships had been warned not to approach the Strait, one of the world's busiest energy transit chokepoints.

Hashemi later said that the warning fire had ceased and that vessels were receiving no answer when asking via radio whether the passage was indeed closed.

At the same time, the Persian Gulf Strait Authority announced that ships that submit "compliant transit requests" would be allowed to transit the Strait "during the announced period".

The maritime authority said crew would have to make their requests "at least 48 hours" before arriving at the Strait. It added that it would not charge ships fees for 60 days.

It comes as Israel and Lebanon traded a series of strikes overnight and into Friday.

The Israeli military reported that four of its soldiers had been killed in the south of the country on Thursday, with five others injured in an "explosive drone impact" on Friday.

Israel's Prime Minister Benjamin Netanyahu said he would "not tolerate attacks on our soldiers" and promised to "exact a very heavy price from Hezbollah".

Israel's national security minister Itamar Ben-Gvir had earlier called for "all of Lebanon" to "burn" following the attacks.

The Israel Defense Forces carried out strikes across southern Lebanon overnight, targeting what it said were Hezbollah operatives and infrastructure. At least 18 people have reportedly been killed in the strikes so far.

It comes as scheduled talks between the US and Iran on implementing their initial peace agreement in Switzerland were postponed.