Oil prices closed lower on Friday, with U.S. crude settling at $73.41 and Brent at $78.56 per barrel, down 0.9% and 54 cents, respectively. Despite daily declines, both benchmarks posted weekly gains. Tensions in the Middle East, causing companies to reroute shipments around Africa, supported prices. U.S.-Iran clashes and conflicts in the Red Sea contributed to concerns. Unexpectedly low U.S. crude inventories and cold weather disruptions added support. Positive reports from the International Energy Agency and OPEC boosted sentiment, but worries persist over weak global economic growth, exemplified by the UK's 3.2% retail sales drop in December.