TOKYO — Despite slowing demand, fears are mounting that oil prices will top $100 per barrel as tensions in the Middle East multiply, threatening Asia, home to some of the world’s largest net oil importers.

In the first week of October, Iran fired missiles into Israel, which promised to make Iran “pay” for the attack. This led to speculation that Israel might retaliate by striking Iran’s oil infrastructure, or that escalation could lead to a closure of the Strait of Hormuz, a bottleneck of a waterway through which Asia receives 70% of its oil imports.