Iran’s Fars news agency, citing a port official, said black smoke behind Bandar Abbas fish market caused by “enemy projectiles” has set fire to several civilian fishing boats.

Earlier on Tuesday, three civilian vessels were hit in the strait of Hormuz – the most in a single day since late April, according to UN International Maritime Organisation figures.

The renewed hostilities threaten to again disrupt shipping transiting the Gulf channel.

Ending Tehran’s stranglehold on the strategic waterway, which disrupted global oil and gas supplies and drove up fuel and food prices, had been a key demand in previous negotiations.

However, the initial deal reached between the US and Iran – known as the Islamabad memorandum of understanding – only secures safe, toll-free passage of the strait for 60 days, pending the outcome of a final agreement on Tehran’s disputed nuclear plans.

The pact also leaves it to Iran and Oman, in conjunction with other Gulf states, to “define the future administration and maritime services in the Strait of Hormuz”.

In the meantime, Iran has continued to try and exert leverage over the channel, including demanding ships seek permission to transit and raising the spectre of future charges.

This has included claims by Tehran that only it is permitted to carry out mine clearance in the strait under the terms of the interim agreement, after Oman agreed to work with Britain and France to make sure the sea route remained open.

US strikes in Iran targeted their air defense systems, coastal surveillance systems, surface-to-air missiles, anti-ship cruise missiles, drone launch sites, an unnamed US official told Reuters.

Kazem Gharibabadi, Iran’s deputy foreign minister for legal and international affairs, said the US Treasury’s earlier decision to revoke a license that had authorised the sale of Iranian oil, was a “blatant violation” of Article 10 of the Islamabad Memorandum of Understanding.

He added the subsequent strikes “constitute a serious violation” of Articles 1 and 2 of the agreement, which was signed last month.

Gharibabadi insisted Iran would “take decisive actions to safeguard its national interests and security”.

There have been explosions in several areas in the south of Iran, according to local media.

Several explosions have been reported in the port city of Sirik, near the Strait of Hormuz, while six projectiles reportedly struck the area of Taheroui Pier.

Explosions were also heard in Qeshm Island, the largest island in the vicinity of the Strait of Hormuz, and Bandar Abbas.

Earlier in the day, Qatar warned Iran it will bear full legal responsibility after three tankers, including a Qatari LNG vessel, were struck within hours in the strait of Hormuz.

All three were hit close to Oman, which had suggested a new shipping corridor close to its coastline – a proposal Iran opposes as it wants to charge ships to use the waterway.

Iran blamed the US for the incident, saying Washington’s efforts to open up new routes through the strait constituted a breach of the memorandum of understanding the two parties had signed.

Tehran claims the memorandum is specifically worded to leave it, in consultation with Oman, to manage the reopening of the strait with the aim of commercial traffic returning to prewar levels within 30 days.

At a briefing in Tehran, foreign ministry officials insisted Iran had a right to impose fees on all ships using the strait.