He said US President Donald Trump "divides the country into two groups: hardliners and moderates, and then immediately talks about a naval blockade to force Iran into submission through economic pressure and internal discord," state TV reported.

With the killing of numerous Iranian leaders by US-Israeli strikes, including supreme leader Ali Khamenei, there has been widespread speculation over the balance of power within the Islamic republic.

Trump said earlier this month that the government of Iran was "seriously fractured, not unexpectedly so".

Ghalibaf, a powerful figure, has grown in prominence since the start of the war and was the lead negotiator in the so far only round of direct US-Iranian talks.

"The enemy has entered a new phase and wants to activate economic pressure and internal division through naval blockade and media hype to weaken or even make us collapse from within," he said on Wednesday.

He called for "maintaining unity" as the only solution.

The United States has been blockading Iranian ports in retaliation for Tehran's closure of the Strait of Hormuz, a vital shipping route for oil and gas.