North Koreans went about their daily business as normal in Pyongyang on Thursday, a report said, despite a tense atmosphere in the city following the bombardment of a South Korean island two days earlier.

State television and radio in the North interspersed repeated broadcasts of foreign ministry and military statements about Tuesday's shelling with martial music, Japan's Kyodo News agency said.

Pyongyang has insisted its artillery barrage on the island of Yeonpyeong, which killed four people, was in response to the South firing shells into its territorial waters.

Many buildings in the centre of the secretive communist state's capital were lit up colourfully and major streets were decorated with illuminations, despite there being no major anniversaries this month, Kyodo said.

As temperatures fell to around freezing, Pyongyang residents lined up for buses and made their way home from work as normal, the agency said.

One resident quoted by Kyodo backed his country's strike against its southern neighbour.

"Our army showed a firm response against South Korea's provocation," the unnamed man told Kyodo.

The agency also reported more rigorous security measures at Pyongyang airport, with officials checking items such as hairdryers and electronic dictionaries as well as the usual laptop computers and mobile phones.

State media also carried reports of leader Kim Jong Il's "field guidance" trips to factories, farms and military units around the country, Kyodo said.

Pyongyang has warned it could follow up this week's deadly shelling with more attacks.

Share This Article With Planet Earth