Renewed missile exchanges between the US and Iran and uncertainty over the Strait of Hormuz drove declines in markets globally on Monday, with rising oil prices adversely affecting travel and leisure shares.Wall Street indexes fell as the escalation in conflict unnerved investors, while chip stocks extended their recent slide.In Europe, Irish airline Ryanair, Lufthansa and TUI all fell between 1.1 per cent and 4.1 per cent, as oil prices spiked by more than 4.8 per cent on the day. DublinThe ISEQ-all share index kicked off the week on a moderate decline, with the index dropping by 0.87 per cent to 13,762.67. Driving this was Ryanair, which dropped by 2 per cent over the course of the day, as geopolitical uncertainty and higher oil prices adversely-affected airline stocks.Insulation specialist Kingspan also saw a significant drop of 1.5 per cent. Banking stocks ran flat as AIB and Bank of Ireland shares fell by 0.29 and 0.34 per cent respectively. Kerry Group, meanwhile, saw a marginal rise of 0.12 per cent to €82.85. LondonUK’s FTSE 100 ended flat on Monday as a rally in oil prices ​boosted energy stocks, helping offset losses in financials and mining stocks as investors assessed renewed military exchanges between the US and Iran.The blue-chip FTSE 100 index ended flat at 10,498.3 points, while the ​midcap FTSE 250 edged 0.1 per cent higher.Vodafone topped the FTSE 100 with a 5.5 per cent gain, extending Friday’s rally, after French billionaire Xavier Niel said he planned to buy a near $6 billion stake in the telecoms group from UAE’s e&.Homebuilders rose ​2 per cent following a media report that Andy Burnham, ​who is likely to be the next British prime minister, is set to ‌review plans to bring back the “Help to ​Buy” scheme which was designed to help first-time buyers afford properties.Watches of ⁠Switzerland Group jumped 4.2 per cent after Reuters ⁠reported the ​luxury watch retailer has held talks in recent months over potential take-private offers.PageGroup surged almost 20 per cent after the recruiter beat second-quarter gross profit forecasts.EuropeEuropean shares were subdued on Monday as investors largely ‌stuck to the sidelines after renewed tensions in the Middle East, while counting on the upcoming earnings season to provide fresh momentum.The pan-European STOXX 600 ​index was flat at 641.01, after logging its sharpest weekly loss since April on Friday.Energy stocks rose ⁠2.2 per cent and were the biggest gainers on the STOXX 600, while defence shares slipped 1.4 per cent.The tech sector also came under pressure, down 0.6 per cent, tracking declines in global peers. SK ⁠Hynix’s South Korean-listed shares shed 15.4 per cent after surging ​on their Nasdaq debut on Friday.Kongsberg Gruppen fell ⁠6.8 per cent after the Norwegian defence and technology firm’s second-quarter orders missed expectations, while a recent spin-off affected its cash flow more than expected.Dulux paint maker AkzoNobel was slightly higher after Nippon Paint offered to ​buy the firm’s decorative paint business for €7.5 billion ($8.55 billion).New YorkThe S&P 500 and the Nasdaq fell on Monday ‌as a fresh escalation between the US and Iran in the Gulf pushed oil prices higher and unnerved investors, while chip stocks extended their recent declines.Memory-chip makers, which have had a sharp rally this year, extended their recent pullback, with Micron Technology and Sandisk. They were among the top decliners on the benchmark S&P ⁠500 index.The Philadelphia SE Semiconductor index fell, having significantly dropped from its record high hit in ‌late June.US-listed shares of South Korean chipmaker SK ​Hynix fell 7 per cent after a blockbuster Nasdaq debut on Friday.Crude futures rose after investors weighed the renewed threat ​to the shipping route. The tech-heavy Nasdaq led declines, with semiconductor stocks among the biggest losers.Additional reporting by Reuters.