Iran’s Revolutionary Guards said Sunday they would fully shut the strategic Strait of Hormuz if U.S. President Donald Trump follows through on threats to target the country’s energy facilities, marking a sharp escalation in tensions as the conflict enters its fourth week.

Trump on Saturday threatened to "obliterate" Iran's power plants if Tehran did not fully reopen ⁠the ⁠Strait of Hormuz within 48-hours, suggesting a significant escalation barely a day after he talked about "winding down" the war, now ⁠in its fourth week.

In their Sunday statement, Iran's Revolutionary ​Guards also said companies with ​U.S. shares will be 'completely ⁠destroyed,' if ‌Iranian ‌energy facilities were ⁠targeted ‌by Washington and energy ​facilities in countries ⁠that host ⁠U.S. bases will ⁠be 'lawful' ​targets.

"If the United States' threats regarding Iran's power plants are carried out... the Strait of Hormuz will be completely closed, and it will not be reopened until our destroyed power plants are rebuilt," the military's operational command Khatam Al-Anbiya said in a statement carried by state television.

Iran has already all but choked off the vital waterway, but a relatively small number of vessels have been able to transit it – around 5% of its pre-war volume, according to analytics firm Kpler.