Iran warns of 'surprise' move to be 'remembered for centuries' as Middle East crisis deepens

Iran issued a chilling threat as tensions of the persisting conflict with Israel deepens, with claims of a "surprise" on Wednesday night "the world will remember for centuries."

This came after rising fears of U.S. intervention in the Iran-Israel air war as the conflict entered its sixth day with no signs of cooling.

Iran and Israel launched some new rounds of missile strikes at each other after U.S. President Donald Trump called for Tehran's "unconditional surrender."

The Iranian state television ominously reported that "a great surprise will occur - one that the world will remember for centuries" without specifying details.

Iran has said it would retaliate against U.S. bases if Washington joins the war on the side of its close ally Israel. 

A source with access to U.S. intelligence reports said Iran had moved some ballistic missile launchers, but it was difficult to determine if they were targeting U.S. forces or Israel.