HONG KONG, April 29 -- Oil prices soared more than five per cent to a fresh four-year high Thursday while stocks fell after Donald Trump warned the US blockade of Iranian ports could last months as peace talks remained stalled.

While Tehran submitted a fresh proposal this week to reopen the crucial Strait of Hormuz, the US president reportedly did not believe it was negotiating in good faith.

The Wall Street Journal said he had told national security officials to prepare for a long blockade to compel the Islamic republic to give up its nuclear programme.

At a meeting of oil executives Tuesday, he discussed efforts "to alleviate global oil markets and steps we could take to continue the current blockade for months if needed and minimise...