Iran has said it is closing the Strait of Hormuz, just days after it signed a ceasefire deal with the US.The Islamic Republic warned all vessels not to approach the shipping lane, which plays a vital role in global trade, and blamed continued Israeli strikes in Lebanon. Citing a US 'breach of contract' and Israel's 'continuous and relentless violation of the ceasefire in southern Lebanon', Iran's central military command announced Saturday 'that the Strait of Hormuz will be closed to vessel traffic'. It warned all ships that their security would be at risk if they attempted to traverse the strait, through which some 20 per cent of the world's oil and liquefied natural gas travels each year. It comes after US President Donald Trump said ships had begun transiting the strait after the interim agreement with Iran was signed earlier this week.A statement on Iranian state television added that 'if the aggression continues, subsequent steps have been planned'.Minutes later, the state broadcaster said the country's negotiating team was still heading to Switzerland, a trip that was originally planned for Friday but was cancelled.The interim deal between the US and Iran, known as the 'Memorandum of Understanding', explicitly pledged an 'immediate and permanent termination of military operations on all fronts, including in Lebanon'. The Islamic Republic warned all vessels not to approach the shipping lane, which plays a vital role in global trade, and blamed continued Israeli strikes in Lebanon Israeli airstrikes have taken place across southern Lebanon since midnight, with intense bombardments targeting the city of Nabatieh and its surrounding areasBut fighting continued in Lebanon overnight and into Saturday, with Israeli troops also still occupying large parts in the south of the country. It comes just hours after reports emerged of a ceasefire deal between Israel and Hezbollah - Iran has demanded since the beginning of negotiations that Lebanon be included in any ceasefire.And the Iranian threat came minutes after US Vice-President JD Vance told journalists 'things are going well' in negotiations and he expects to travel to Switzerland soon.'I expect that I will leave some time in the next couple of days, but you know it's always a delicate coordination dance,' Vance told Fox News, two days after unexpectedly postponing a planned trip to discuss next steps on the US-Iran agreement to end the war.Vance said US negotiators Jared Kushner and Steve Witkoff were already in Switzerland, handling 'some of the technical elements' of the talks, and had reported that 'things are going well'.But Iran's Foreign Ministry spokesperson Esmail Baghaei has signalled that little might happen until Iran feels the US is living up to the deal.'This trip is therefore about demanding that the other side fulfill its obligations,' he said, adding that negotiations toward a final agreement will begin only once key commitments, including an end to fighting in Lebanon, are upheld.'If any part of these understandings, any part of these commitments, is not implemented, then the memorandum of understanding as a whole will be jeopardised,' Baghaei said.The new threats from the Iranian regime come after Israeli strikes on southern Lebanon continued on Saturday and killed at least 16 people, including two children, hours after reports emerged of a ceasefire agreement. Seven people remained trapped under the rubble after the strikes hit the southern town of Nabatieh and nearby villages, Lebanon's National News Agency said.Mediators were scrambling to halt the fighting between Israel and the militant Lebanese Hezbollah group, after heavy exchanges on Friday killed at least 83 people in Lebanon and four Israeli soldiers.An Israeli military official said Hezbollah had fired more than 50 projectiles at Israeli forces in southern Lebanon overnight, prompting the military to start targeting the militant group there. The official said it struck dozens of Hezbollah targets and militants in southern Lebanon, including rocket-launching positions and Hezbollah command centres. A rescue worker searches for survivors under rubble in Qennarit village, southern Lebanon, on Saturday The Strait of Hormuz had only just reopened to marine traffic following the signing of an interim ceasefire between the US and IranOn Friday, Israeli ambassador to Washington, Yechiel Leiter, said on X that Israel 'remains firmly committed to an immediate ceasefire' if Hezbollah honours the agreement and ceases hostilities.On Saturday, Hezbollah said it had committed to the ceasefire but blamed Israel for violating it several times on Friday night. A statement issued by the group's military wing said it would abide by the ceasefire but would also repel attacks by Israeli troops.On Saturday, Lebanese authorities said more than 4,000 people have been killed since the start of the conflict, including 83 on Friday.Israeli prime minister Benjamin Netanyahu previously vowed to keep Israeli forces in southern Lebanon until any threat to Israel is eliminated. Hezbollah has refused to halt its attacks unless Israel commits to withdrawing from Lebanon, which Iran says is also a condition of the interim deal.Iran moved to effectively close the Strait of Hormuz after the US launched its attacks with Israel at the end of February.There have been a series of reports of attacks on and damage to commercial vessels throughout the conflict. Today, US Central Command sad that 55 merchant ships safely transited the state on June, containing more than 17million barrels of oil.