Al Qaeda's leader Ayman al-Zawahiri has called for lone wolf attacks in the US and the west.
In an audio recording posted on Sunday, the terrorist group's boss called on Muslims to "harm the countries of the crusader coalition."
He ordered his followers to "focus on moving the war to the heart of the homes and cities of the crusader West and specifically America."
The recording is thought to be around two months old, as it refers to former Taliban leader Mullah Omar as being alive.
His words come just days after another recording was released, claiming to be from al-Zawahiri, which dismissed fellow militants of the so-called Islamic State.
He said: "We don't recognise this caliphate."
He added that IS had made "big mistakes" but hinted there may still be room for cooperation between the two groups, urging greater unity between militants.
Reference to events show that recording was probably made at least eight months ago.
