"This was an attack on the press. It was an attack on freedom of speech.

"It's just as important as any other tragedy."

In Australia, the national flag can be flown at half-mast at the discretion of local authorities. In the US, a presidential proclamation is required to mark mourning nationwide, but communities or government departments can choose to do so locally.

Buckley said his wife talked him out of pushing ahead without the President's approval and lowering flags in Annapolis, the capital of the US state of Maryland.

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"At this point in time, it would start to polarise people and I don't want to make people angry," Buckley, 55, who moved to the US in 1992 and has become a successful restaurant owner in Annapolis, said.

Jarrod Warren Ramos, 38, is accused of walking into The Capital newspaper's office on Thursday, local time, and shooting dead five employees with a shotgun.

Ramos, who reportedly had a long-running dispute with the newspaper, was arrested in the newsroom just minutes after he opened fire.