Japan says has strong concerns over North Korea's 'provocative acts'

"North Korea should exercise self-restraint in making provocative acts," Chief Cabinet Secretary Yoshihide Suga told a news conference.

South Korea fired a barrage of artillery rounds into North Korea on Thursday after the North shelled across the border to protest against anti-Pyongyang propaganda broadcasts by Seoul.

(Reporting by Kaori Kaneko; Editing by Dean Yates)