MT Newswires -ShutterstockAustralian shares closed lower on Thursday, as investors reacted to fresh escalations in the conflict in the Middle East as well as the US Federal Reserve's monetary policy decision. The S&P/ASX 200 Index fell 0.78%, or by 70.90 points, to close at 8,967.70 after setting a new 100-day high. Brent crude oil futures fell to trade around $91 per barrel even as the US conducted fresh strikes against targets in Iran. The US Federal Reserve, under new Chair Kevin Warsh, kept monetary policy unchanged. It added that the Lytton refinery in Queensland will undergo major maintenance starting in August.