SATV, Kathmandu, Mar. 23 - Major stock markets in Asia slumped on Monday after Washington and Tehran threatened to intensify hostilities, as the Iran war enters its fourth week.

Japan's benchmark Nikkei 225 index was almost 3.6% lower, while South Korea's Kospi fell by almost 6%.

US President Donald Trump warned on Saturday that he would "obliterate" Iranian power plants if Iran did not open the key Strait of Hormuz shipping route. Iran said it would respond to any such strikes by targeting key infrastructure in the region, including energy facilities.

Japan and South Korea have been particularly impacted by the conflict, as they are heavily dependent on oil and gas that would normally pass through the strait.

Iran has effectively blocked the Strait of Hormuz, one of the world's busiest oil shipping channels, since the US and Israel attacked the country on 28 February.

About 20% of the world's oil and liquefied natural gas (LNG) usually passes through the waterway - and the war has sent global fuel prices soaring.

On Monday, International Energy Agency chief Fatih Birol said that the war could see the world facing its worst energy crisis in decades.

Speaking at the National Press Club in Australia's capital, Birol compared the current energy crisis to those of the 1970s and the impact of Russia's 2022 invasion of Ukraine.

"This crisis as things stand is now two oil crises and one gas crash put all together," he said.