The U.S. and Iran threatened direct attacks on regional energy infrastructure Sunday. President Donald Trump issued a 48-hour ultimatum to reopen the Strait of Hormuz. Trump vowed to destroy Iranian power plants if the waterway remains blocked.

The four-week conflict has already pushed global oil and gas prices to multi-year highs. Iran’s military command warned of retaliatory strikes on American energy, information technology, and desalination facilities. Air raid sirens sounded across Israel on Sunday due to incoming Iranian missiles.

Analysts expect the heightened geopolitical uncertainty to pressure global markets during Monday’s opening.