The situation at Japan's damaged nuclear power plant is still serious but does not appear to be deteriorating, said the International Atomic Energy Agency (IAEA) Thursday.

Speaking at the IAEA's press conference on the issue of the quake-damaged plant, Graham Andrews, a senior aide to IAEA chief Yukiya Amano, said that "there had been no significant worsening since yesterday."

Andrews said, the Fukushima plant's Unit 1, 2 and 3 at the moment are in stable condition, sea water are being injected into all three units to cool down the overheated fuel rods, because these three units have got no cooling system.

But he admitted that the situation of Unit 4 is currently unknown and expressed his deep concern. But Unit 5 and 6 remain integral and the temperature is declining, he said.

Radiation in locations around 30 kilometers from the scene of the accident rose significantly in the last 24 hours, he said.

According to IAEA website, Yukiya Amano, the director general of the IAEA, is traveling to Japan to learn more about the crisis at the country's Fukushima Daiichi nuclear plant. And he will arrive at Narita International Airport this morning.

Japanese authorities have informed the IAEA that engineers have begun to lay an external grid power line cable to Unit 2. They plan to reconnect power to Unit 2 once the spraying of water on the Unit 3 reactor building is completed.

The spraying of water on the Unit 3 reactor building was temporarily stopped at 20:09 local time of 17 March.

The IAEA continues to liaise with the Japanese authorities and is monitoring the situation as it evolves.