Iran's Islamic Revolutionary Guard Corps announced on Friday that it had struck and halted two oil tankers that defied its directives while trying to cross the Strait of Hormuz under US military protection, and that four other tankers quickly turned back.

The announcement came as President Donald Trump met his cabinet at Camp David to discuss the Iran conflict, inflation and the approaching midterm elections; White House press secretary Karoline Leavitt had identified the Iran war as the meeting's main agenda.

Iran and the United States both said two separate sea lanes had been designated for transit through the strait, with Iran striking tankers on the southern route near Oman and the United States targeting vessels and ports that violate its blockade.

Movement through the strait has nearly halted since the two countries renewed fighting two weeks ago, and crude prices rose above $90 a barrel after US strikes on Iran on Thursday in response to an attack on a US base in Jordan.

Kuwait's Defense Ministry said it shot down an Iranian drone aimed at important and military sites, with no casualties reported.

Israeli forces set off huge explosions overnight near Beaufort Castle in southern Lebanon, saying they targeted Hezbollah tunnels and infrastructure, while Lebanese officials accused Israel of breaking the ceasefire and the Israeli military said it was securing northern residents.

An opinion poll conducted this week found that only one in three Americans supported the war, the lowest level since it started, and the Senate rejected by a single vote a measure to force the president to end the conflict.

The conflict has inflated energy company earnings, with ExxonMobil's profit roughly double and Chevron's more than five times their year-earlier levels.