European stocks held most of their morning losses to close lower on Monday, pressured by a slight pivot towards safety as tensions in the Middle East escalated. The STOXX 50 dropped 0.2% to close at 5,222 and the pan-European STOXX 600 fell 0.3% to close at 535. US forces used bunker buster missiles to strike Iranian nuclear infrastructure over the weekend, its first direct attack in the current conflict, to open a new degree of escalation. Besides vowing to retaliate, Iran threatened to prohibit the passage of tankers through the Strait of Hormuz, but the constant flows of tankers through the chokepoint since yesterday prevented a rally in oil and gas prices. Novo Nordisk shares fell 5.3% after it ended its retail agreement through Hims & Hers. Also, insurers fell on risks of military action for tankers and infrastructure, with AXA and Munich Re dropping more than 3%.