Republican presidential candidate Mitt Romney has criticised US President Obama on foreign policy and has called for a change of course in the Middle East.

With four weeks to go before the election, polls show Obama retains a foreign policy lead over his rival.

Romney has repeatedly criticised the president for a foreign policy that he believes has left the US less respected and less powerful in the world.

In a speech at the Virginia Military Institute Romney also pledged to put Iran on notice over its nuclear plans and called for arms to go to Syrian rebels.