The United Nations is closely following tensions between South and North Korea with "with serious concern," a U.N. spokesperson said Thursday, after the two Koreas exchanged artillery fire across their border.
  

"What we can say, on the exchange of artillery fire that we saw reports of today, is that we are closely following the developments with serious concern," Eri Kaneko, associate spokesperson for Secretary-General Ban Ki-moon, said at a briefing.
  

Earlier in the day, North Korea fired a shell toward a South Korean front-line military unit in the western area of the heavily fortified border in apparent anger over South Korea's border propaganda broadcasts. South Korea fired back dozens of rounds.
  

No damage has been reported in the exchange of fire. (Yonhap)