A white gunman with a long-standing grudge against a newspaper in the US city of Annapolis blasted his way through its newsroom with a shotgun and smoke grenades, killing at least five people, mostly journalists, in what police called a targeted attack.

The shooting at the Capital Gazette newspaper in Annapolis, Maryland, nearly 50 km from Washington, that also injured three others, is said to be one of the worst attacks on the media in decades in the US. The shooter identified as Jarrod Warren Ramos, 38, has been arrested and is being charged with five counts of first-degree murder.