North Korea a big worry: Obama

US President Barack Obama has taken aim at North Korea, calling it a "big worry", as tensions escalate following Pyongyang's fourth nuclear test, conducted in January.

He made the remark yesterday at a briefing on the sidelines of Group of Seven talks at which North Korea's provocations and its nuclear ambitions are among the topics on a packed agenda.

"It is not the thing that poses necessarily the most immediate risk. (But) when you have such an unstable regime that is so isolated, that poses the kind of medium-term threat that we have to pay a lot of attention to," Mr Obama said, adding that the North was "hell bent" on getting atomic weapons.

AGENCE FRANCE-PRESSE

Leaders try out self-driving cars

Some Group of Seven leaders travelled in self-driving cars during a break at the annual leaders' summit yesterday.

Canadian Prime Minister Justin Trudeau and Italian Prime Minister Matteo Renzi were among those who rode in the back of the cars being developed by Japanese manufacturers.

Japanese Prime Minister Shinzo Abe hopes to employ a self-drive service in time for the 2020 Tokyo Olympics to ease road congestion.

REUTERS