The International Atomic Energy Agency (IAEA) described the situation at the Fukushima nuclear power plant as very serious, but that it appears to have become stable.

Graham Andrew, a senior aide to IAEA chief Yukiya Amano told reporters that there had been no significant worsening over the past 24 hours at the quake-damaged plant.

However, Andrews also warned that the crisis could change rapidly by either improving (if emergency workers are able to cool down the overheated reactor complex), or, in the worse-case scenario, could escalating into a catastrophe.

It hasn't gotten worse, which is positive, But it is still possible that it could get worse, he said. We could say it's reasonably stable at the moment compared to yesterday.

Amano has departed for Tokyo to closely observe efforts by Japanese nuclear technicians to prevent further radiation leakage from the crippled power plants.

However, it was unclear what Amano’s itinerary in Japan could consist of.

We don't have a fixed schedule and don't have all the information so we will be thinking on our feet, Amano told reporters prior to his departure.

Japan is not alone, the international community is standing by Japan. We have lots of offers of assistance to Japan and I would like to convey this message to them.