Dubai, April 23 -- Iran fired on three ships in the Strait of Hormuz and seized two of them on Wednesday, intensifying its assault on shipping in the key waterway. The attacks came a day after US President Donald Trump extended a ceasefire while maintaining an American blockade of Iranian ports. The standoff between the US and Iran has effectively choked off nearly all exports through the strait - where 20% of the world's traded oil passes in peacetime - with no end in sight. Iranian media said the paramilitary Revolutionary Guard was bringing the two ships to Iran, marking a further escalation. The conflict has already sent gas prices skyrocketing far beyond the region and raised the cost of food and a wide array of other products. The price of Brent crude oil, the international standard, nosed over $100 per barrel, marking a 35% increase from prewar levels, but stock markets still appear to be shrugging it off. The European Union energy commissioner, Dan Jørgensen, warned of lasting impact for consumers and businesses, likening it to other major energy crises over the last half-century. He said the disruption is costing Europe around 500 million euros ($600 million) each day. Iranian media said the MSC Francesca and the Epaminondas were being escorted to Iran. The US had earlier seized two Iranian vessels as the ceasefire talks were due to take place in Pakistan. Technomar, the management company behind the Liberian-registered Epaminondas - which was headed to the Mundra port in India - said it was "approached and fired upon by a manned gunboat" off the coast of Oman. It said the ship's bridge had been damaged. A second cargo ship came under fire hours later, with no report of damage, though the vessel was then stopped in the water. No injuries to the crew of either vessel were reported. The MSC Francesca's owner could not be immediately reached for comment. The Guard attacked a third ship, identified as the Euphoria, which had become "stranded" on the Iranian coast, Iranian media reported, without elaborating. There have been more than 30 attacks on ships in the Mideast since the US and Israel launched the war on February 28 with a surprise attack on Iran. Before then, the strait was open for all traffic. Vortexa, an analytics firm focusing on global energy and freight markets, said it has recorded 34 movements of sanctioned and Iranian-linked tankers in and out of the Persian Gulf in the week after the U.S. imposed its blockade on April 13. The firm identified 19 outbound and 15 inbound movements. Six of the outbound movements were "confirmed laden with Iranian crude, representing about 10.7 million barrels," it said in an email. It was not immediately clear whether all those barrels reached markets overseas. Iran's ability to restrict traffic through the strait - which leads from the Persian Gulf to the open ocean - has proved a major strategic advantage. While the ceasefire means that American and Israeli airstrikes have stopped in Iran - and Tehran's missiles no longer target Israel and the wider Middle East - the maritime standoff continues and could escalate further. Without any diplomatic agreement, the attacks will likely deter ships from even attempting to pass through the waterway, further squeezing global energy supplies. The night before, hard-line supporters of Iran's theocracy held rallies in which the Guard showed off missiles and launchers - a sign of defiance to Israel and the US, which devoted much of their airstrike campaign to destroying the country's ballistic missile arsenal. Iranian Foreign Ministry spokesperson Esmail Baghaei told state TV that Iran has not decided whether to take part in a new round of negotiations with the US scheduled for later this week. He accused the United States of a "disregard and lack of good faith" in the negotiations. Mojtaba Ferdousi Pour, the head of the Iranian mission in Egypt, had earlier told The Associated Press that no delegation would go to Pakistan until the U.S. lifts its blockade....