The US military said it had completed a new wave of strikes targeting Iranian military command centres, missile and drone launch sites, air defence systems and maritime capabilities.
US Central Command (Centcom) said the operation was intended to further degrade Iran s military infrastructure following recent attacks that killed at least three American service members.
Iran responded by launching attacks on US military assets in Kuwait and Bahrain, targeting air defence systems, radar installations and administrative facilities.
The Islamic Revolutionary Guard Corps (IRGC) warned that Washington should prepare for "more decisive and powerful" waves of drone and missile attacks.
The Guards also claimed to have attacked infrastructure belonging to US technology company Amazon in Bahrain, although Bahraini authorities did not confirm the incident and Reuters said it could not independently verify the claim.
Iran also tightened its control over the Strait of Hormuz, announcing that Revolutionary Guards had intercepted two "non-compliant" oil tankers attempting to transit the strategic waterway.
Separately, the UK Maritime Trade Operations (UKMTO) reported that projectiles struck two tankers off the coast of Oman in separate incidents, adding to concerns over the safety of maritime traffic in the region.
US President Donald Trump warned that Iran would pay "many times over" for every American soldier killed, while Iranian President Masoud Pezeshkian described the conflict as having become "a full-scale war."
The Pentagon said nearly 100 US service members have been wounded since July 7, with most suffering minor concussions.
Meanwhile, Yemen s Houthi movement threatened to impose a blockade on Saudi ports, a move that could significantly disrupt Riyadh s ability to export oil through the Red Sea and have serious implications for global energy markets.
Saudi Arabia condemned the threat, describing the Houthis as a "terrorist militia" and reaffirming its support for Yemen s internationally recognised government.
The latest escalation comes after an April ceasefire and a June diplomatic framework collapsed, prompting Tehran to reimpose restrictions in the Strait of Hormuz while Washington reinstated a blockade on Iranian ports.
Oil prices briefly climbed to a one-month high before easing, as traders weighed the potential impact of prolonged disruption to one of the world s most important energy shipping routes.
Despite the renewed fighting, diplomatic contacts have not completely broken down. Iranian Foreign Ministry spokesperson Esmaeil Baqaei said indirect exchanges with the United States through mediators were continuing.
Separately, Iranian Interior Minister Eskandar Momeni arrived in Islamabad for a two-day visit, where he is expected to meet Prime Minister Shehbaz Sharif and Chief of Defence Forces Field Marshal Syed Asim Munir.
In Washington, Lebanese President Joseph Aoun is also scheduled to meet President Trump as international pressure grows on Beirut to disarm Hezbollah, a key condition set by Israel for withdrawing its forces from southern Lebanon.
