Sparked by a US-Israeli offensive launched against Iran on February 28, the war has rippled across the Middle East, creating global economic turmoil.

More than a month in, US President Trump claimed Wednesday that Iranian President Masoud Pezeshkian was seeking a ceasefire, a claim Tehran has denied.

"Attacking Iran's vital infrastructure -- including energy and industrial facilities -- directly targets the Iranian people," Pezeshkian said in an open letter, published to his website Wednesday.

"Beyond constituting a war crime, such actions carry consequences that extend far beyond Iran's borders."

They sow "instability, increase human and economic costs", and plant "seeds of resentment that will endure for years", he continued.

"Exactly which of the American people's interests are truly being served by this war?"

Casting the conflict as costly for both sides, Pezeshkian asked if there had been "any objective threat from Iran to justify such behaviour".

He also questioned whether Washington entered the war "as a proxy for Israel, influenced and manipulated by that regime".

"Is 'America First' truly among the priorities of the U.S. government today?" Pezeshkian asked.

He also said ordinary Americans were not Iran's enemy, "even in the face of repeated foreign interventions and pressures".

His letter came ahead of US President Donald Trump's prime-time address to Americans on the Iran war in the face of plunging approval rates, economic jitters and spiralling diplomatic fallout.

Trump on Wednesday said he would consider a ceasefire only when the Strait of Hormuz was reopened, with Tehran's effective closure of the vital oil corridor sending shockwaves through the global economy.