The United States will carry out aggressive strikes on Iran over the next two to three weeks and is nearing completion of its main strategic objectives in the ​war, President Donald Trump said in a prime-time address to the nation on Wednesday.

Addressing a war-weary US public, Trump said his military had delivered "swift, decisive, overwhelming victories on the battlefield," during 32 days ‌of military strikes and that Iran was no longer a security threat.

"I can say tonight that we are on track to complete all of America's military objectives shortly, very shortly," Trump said in a nationally televised address.

"We're going to hit them extremely hard over the next two to three weeks. We're going to bring them back to the Stone Ages where they belong."

Thousands of people have been killed across the Middle East since 28 February, when the US and Israel struck Iran, triggering Iranian attacks on Israel, US bases and ​the Gulf states, while opening a new front in Lebanon.