DUBAI, United Arab Emirates — The U.S. reimposed a naval blockade on Iran and intensified its airstrike campaign Wednesday in retaliation for Tehran’s attacks on ships trying to pass through the Strait of Hormuz. The American strikes hit an Iranian army barracks, killed at least seven troops and wounded hundreds of people across the country, Iranian officials said. Days of back-and-forth strikes by the U.S. and Iran across the Middle East — and renewed threats to the waterway crucial to global energy supplies — have shredded the interim deal to end the conflict and the region could tip back into all-out war. The U.S. first imposed a blockade in April and lifted it last month after signing the interim deal that paused the fighting and set a 60-day period for negotiations over issues such as Iran’s nuclear program. Those talks have stalled as fighting over the Strait of Hormuz has intensified. When the U.S. and Israel launched the war on Iran on Feb. 28, Tehran effectively closed the waterway to shipping traffic — a move that sent the price of oil, fertilizer and many other go