Dan Mitchinson: US correspondent on threats from Iran inspiring increased security around Donald Trump in recent weeks - Heather du Plessis-Allan Drive

US officials have confirmed threats from Iran to assassinate Donald Trump had prompted increased security around him in recent weeks.

It appears unrelated to the assassination attempt in Pennsylvania over the weekend.

However, this has raised questions surrounding the apparent lapses that led to the shooter getting close enough to fire at Trump in the first place.

US correspondent Dan Mitchinson says the incident left behind plenty of unresolved questions.

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