DUBAI/JERUSALEM — The US-Israeli military campaign against Iran entered its sixth day on Thursday as residents in Tehran reported the heaviest wave of bombing since the conflict began.

Explosions echoed across several districts of the Iranian capital as Israeli forces launched a new round of strikes targeting government and military facilities.

“Today is worse than yesterday. They are striking northern Tehran. We have nowhere to go,” said Mohammadreza, a 36-year-old resident, speaking by phone while blasts sounded in the background.

Meanwhile, Iran vowed retaliation after the United States sank an Iranian warship near Sri Lanka in a torpedo attack on Wednesday that reportedly killed more than 80 sailors. Iranian Foreign Minister Abbas Araghchi warned Washington would “bitterly regret” the strike, while a senior Revolutionary Guard commander said Iranian forces would confront American troops wherever they are deployed.

Authorities in Tehran also postponed a planned three-day mourning period for slain Supreme Leader Ali Khamenei, citing security concerns. Khamenei was reportedly killed during the opening phase of the US-Israeli air campaign, an unprecedented assassination of a sitting national leader in an airstrike.

Israeli officials say the next phase of their campaign will focus on underground bunkers storing Iran’s ballistic missiles. Washington says its goal is to limit Iran’s ability to project military power beyond its borders.

The conflict is also shaking global energy markets. Iran’s Revolutionary Guards claimed they struck a US tanker in the northern Gulf, while tensions mounted around the Strait of Hormuz, a critical route for roughly 20% of the world’s oil shipments.