Washington: A mysterious explosion on Thursday at an Iranian space centre prompted speculation that it was US sabotage, rather than an accident, that was responsible for the third successive failure of Tehran's efforts to show it could loft satellites into orbit.

The satellite image shows activity at the Imam Khomeini Space Centre in Iran's Semnan province. Credit:AP

As pictures from commercial satellites of a rocket's smoking remains began to circulate, President Donald Trump denied Friday on Twitter that the United States was involved. It was an unusual message because the Iranian government had neither acknowledged the accident nor blamed the United States.

His tweet ended with an apparent taunt: "I wish Iran best wishes and good luck in determining what happened" in the fiery accident.

But Trump also included in his tweet a high-resolution image of the disaster, immediately raising questions about whether he had plucked a classified image from his morning intelligence briefing to troll the Iranians.