TEHRAN, April 30 -- President Donald Trump warned Tehran on Wednesday that it should "get smart soon" and capitulate to Washington's demands for tight controls on its nuclear programme, as a US naval blockade turned the screws on Iran's economy.

The United States could extend its naval blockade of Iran for months more, oil executives were told in a meeting with Trump, an official said, after press reports that he had rejected Iran's latest proposed deal to reopen the Strait of Hormuz.

"Iran can't get their act together... They better get smart soon," Trump posted on his social media platform, above a mocked-up picture of himself toting a rifle in front of explosions wrecking a desert fortress and the slogan: "No more Mr. Nice Guy!"

Acc...