British defense secretary Philip Hammond
British defense secretary Philip HammondAFP/File

The Australian and British foreign ministers Sunday slammed the killing of a Japanese journalist by Islamic State (ISIS) as they vowed to tackle the jihadi terrorist threat at defense talks in Sydney.

British Foreign Minister Philip Hammond is in Australia for the annual meeting with his counterpart Julie Bishop, with efforts to counter terrorism and foreign fighters high on the agenda.

"I wanted to extend Australia's deepest condolences to the people and government of Japan," Bishop told AFP.

"The depraved behavior that has led to the killing of two Japanese nationals is an unspeakable atrocity and we are united in our resolve to counter terrorism in all its forms wherever it occurs."

Hammond echoed the foreign minister's words and said the allies were committed to combating the "growing challenge of Islamist extremism seeking to break down the structures of nation states".

ISIS claimed in a video released online that it has killed a Japanese hostage, the second beheading of a Japanese captive in a week.

Earlier Sunday, Australian Prime Minister Tony Abbott condemned the purported killing as a "terrible shock" for Japan.

"This just demonstrates how important it is that all countries do what they reasonably can to disrupt and degrade this death cult which has ushered in a new dark age over parts of the Middle East," he said.

Also on the agenda was Russia, with Hammond describing Moscow's actions in Ukraine as "ignoring all the rules of the post-Cold War settlement", and the fight against the spread of the Ebola epidemic.

Australia is helping to staff a 100-bed British-built Ebola treatment center in Sierra Leone.

The pair will be joined by Britain's Defense Secretary Michael Fallon and his Australian counterpart Kevin Andrews in Sydney on Monday.