TEHERAN: Iran unveiled a massive billboard and banners pledging to kill US President Donald Trump across Teheran on Tuesday, bringing to a new level the official rhetoric displayed in the capital.

"We will kill Trump", read the billboard towering over the busy Enghelab Square in Teheran, which depicted the US president behind bars with his head bowed.

New designs of billboards and displays mocking and vowing revenge against Trump have frequently been set up around Teheran since the war began on Feb 28 when US-Israeli strikes killed the Islamic republic's supreme leader Ayatollah Ali Khamenei.

In recent days, renewed diplomatic efforts have been underway to bring Teheran and Washington to negotiate to prevent a resumption in fighting which has spread across the region and driven prices up globally.