World News Update, what you need to know

Lawyers for Bali Nine duo Myuran Sukumaran and Andrew Chan are going back to court with their last bid to save the men from the firing squad amid indications from Jakarta it will respect the legal process.

ELSEWHERE:

TUNIS - Gunmen have stormed Tunisia's national museum, killing 20 foreign tourists and two Tunisians in an attack that has raised fears for a rare success story of the Arab Spring.

LONDON - British Prime Minister David Cameron says anyone who helps expose senior politicians and police officers guilty of historic child sex abuse should be protected from prosecution under the Official Secrets Act.

LOS ANGELES - A gunman has killed one person and wounded five others in a shooting spree in Arizona, sparking an ongoing manhunt by SWAT teams, police say.

MIAMI - Last month was the second hottest February in modern history, according to a report by US government scientists who measure the global average land and sea temperature each month.

ANAKKALE - Turkey has marked 100 years since the start of the Gallipoli Campaign by the Allies in World War I, an event seen now as a glorious victory by Ottoman forces and a crucial moment in the formation of the modern Turkish state.

LONDON - The Duchess of Cambridge has told families and volunteers at a children's centre for struggling parents that she is expecting her second child to arrive by the "mid-to-end" of April.