Police attended a property on Worsley Road, Eccles, this morning following a report of concern for the welfare of a man.
Bomb disposal officers are due to make an assessment of a suspicious package found at the property.
A man, aged 35, has been arrested on suspicion of possession of a knife.
Road closures are in place while enquiries continue.
Nearby buildings have been evacuated and a 100m cordon is in place.
We will update the story as we learn more about the situation.