U.S. forces struck three Iranian crude oil tankers on Saturday after Iran fired missiles at a U.S. Navy aircraft carrier and destroyer, U.S. Central Command said. Iran had also launched missiles at U.S. bases around the Persian Gulf earlier in the week. CENTCOM said the tankers were part of a shadow shipping network that channels revenue to the Islamic Revolutionary Guard Corps, and Adm. Brad Cooper said the United States would impose higher economic costs in response to attacks on its ships. The exchange marks a potential new phase in a conflict centered on the Strait of Hormuz, where neither side has achieved its strategic objective. U.S. forces have continued escorting some tankers through the waterway, but Iranian attacks have kept commercial traffic below prewar levels and supported oil prices. The U.S. naval blockade has simultaneously constrained Iranian oil exports and intensified pressure on Tehran's economy. Hamidreza Azizi of the International Crisis Group said Iran's attempted attack on U.S. warships crossed a higher threshold than its earlier attacks on commercial shipping and Gulf bases. The Financial Times reported that Russia is secretly assisting Iran's development of supersonic cruise missiles, which could strengthen Tehran's ability to threaten naval and land targets. The Treasury Department has also pledged wider sanctions against countries facilitating Iran's oil trade and financial transactions. The escalation has returned oil and the Strait of Hormuz to the center of market concerns. Brent crude traded near $96.28 a barrel after fears of disrupted supply helped drive a rally, while higher energy prices, rising Treasury yields and geopolitical risk weighed on equities and crypto assets. The military pressure coincides with an intensifying dispute over Iran's nuclear program and a Western effort to refer Tehran to the U.N. Security Council.