Washington, April 4 -- The White House sent a spending proposal to lawmakers Friday calling for a massive $1.5 trillion US defense budget next year as it faces increased costs due to the war in Iran. President Donald Trump has threatened to extend attacks on civilian infrastructure in Iran after a US strike cut a major highway bridge on Thursday, prompting a defiant response from Iran, which hit a water plant in Kuwait and said more would follow. The total year-on-year increase in Pentagon spending would be the largest since World War II. On Thursday, Trump posted footage on social media showing dust and smoke billowing up as US strikes hit the newly constructed B1 bridge between Tehran and nearby Karaj, which was due to open to traffic this year. In response, Iran's Revolutionary Guardc Corps said it would hit "all assets of the Israeli regime and the US in fuel, energy, economic centres, and power plants across the region". It said countries hosting US bases should make them leave. As the two sides exchanged taunts, an Iranian attack on Friday hit a water desalination and power plant in Kuwait, a major US ally in the region, causing material damage to parts of the facility, Kuwait's electricity and water ministry said. The attack underlined a potentially devastating vulnerability for Gulf countries, which rely heavily on desalination for drinking water. Nearly five weeks after the war started with a joint US-Israeli aerial assault, Trump is under pressure to find a quick resolution. Negotiations conducted via intermediaries with new leaders in Iran have shown little sign of progress, and pessimism at home has been growing, with polls showing most Americans opposed to the war. At the same time, the economic impact has been ratcheting up sharply around the world, with Iran's grip on the strategic shipping lane in the Strait of Hormuz giving it a choke hold on oil and gas supplies vital to the global economy. As he threatened more attacks, Trump said Iran's leadership "knows what has to be done, and has to be done, FAST!" But there has been little sign of acquiescence from Tehran. "Striking civilian structures, including unfinished bridges, will not compel Iranians to surrender," Foreign Minister Abbas Araqchi said. Iranian media have issued daily reports of attacks on civilian sites including schools, pharmaceutical suppliers and health facilities. On Thursday, the century-old Pasteur Institute in the heart of Tehran was severely damaged, the Health Ministry said. On Friday, a drone attack hit a Red Crescent relief warehouse in the Choghadak area of the southern Bushehr province, where Iran's first nuclear power plant is located. As the attacks have continued, over 100 American international law experts said the conduct of US forces and statements by senior US officials "raise serious concerns about violations of international human rights law and international humanitarian law, including potential war crimes". For its part, Iran has continued to strike targets around the Gulf, increasing the already heavy cost of the war on the region and the global economy. As well as Friday's attack on the water plant, Kuwait Petroleum Corporation said its Mina al-Ahmadi refinery had been hit by drones. Fires were ignited at operating units, but no injuries were reported. Other attacks were also reported to have been intercepted in Saudi Arabia and Abu Dhabi. Missile debris landed near the Israeli port of Haifa, site of a major oil refinery. Global financial markets have whipsawed in response to expectations of a possible end to the war and the re-opening of the Strait of Hormuz, which only isolated vessels have been able to transit since the start of the war. In normal times, the Strait is the conduit for around a fifth of the world's oil and natural gas. Its closure has also squeezed shipments of fertiliser, threatening a humanitarian crisis in developing countries in Asia and Africa. On Friday, a container ship belonging to the French shipping group CMA CGM passed through, MarineTraffic vessel tracking data showed, a sign that Iran may not consider France a hostile nation. A liquefied natural gas container ship belonging to Japan's Mitsui OSK Lines also transited the Strait. While most markets in Asia were closed for Easter, Japan's Nikkei share average rallied to trim its losses for the week following global efforts to restore Gulf oil shipments. Oil markets were closed after benchmark US crude prices gained 11% on Thursday after a televised speech by Trump that offered no clear sign of an imminent end to the war....