Oil prices steadied near 3-1/2 year highs on Friday as the prospect of new U.S. sanctions on Iran tightened the outlook for the Middle East supply at a time when global crude production is only just keeping pace with rising demand. The United States plans to reintroduce sanctions against Iran, which pumps about 4 percent of the world’s oil, after abandoning a deal reached in late 2015 that limited Tehran’s nuclear ambitions in exchange for the removal of U.S. and European sanctions. The global oil market is finely balanced, with top exporter Saudi Arabia and No.1 producer Russia having led efforts to curb oil supply to prop up prices. Benchmark Brent crude oil was unchanged at $77.47 a barrel by 0830 GMT. […]