Although U.S. Navy officials are convinced that they would prevail in a fight, Iran’s advances have fueled concerns about U.S. vulnerabilities during the opening hours of a conflict in the gulf.

Increasingly accurate short-range missiles — combined with Iran’s use of “swarm” tactics involving hundreds of heavily armed patrol boats — could strain the defensive capabilities of even the most modern U.S. ships, current and former military analysts say…

The likelihood that Iran would risk an all-out attack on a vastly superior U.S. fleet is judged to be small. But Iranian leaders could decide to launch a limited strike if Israel or the United States bombed the country’s nuclear facilities. Analysts also cautioned that a conflict could be sparked by an Iranian attempt to close the Strait of Hormuz — the narrow passage through which about 20 percent of the world’s oil passes from the Persian Gulf into open seas — in retaliation for international economic sanctions.

In either scenario, Iran’s ability to inflict significant damage is substantially greater than it was a decade ago.