Chinese aid has crossed the border into North Korea to the town devastated by a massive explosion last Thursday.
South Korea and China pledged $1m each in aid
More than 160 people died and 1,300 were wounded in the train blast at Ryongchon, near the Chinese border.
A BBC correspondent said convoys of trucks were loaded with food and tents to provide shelter for the thousands who had lost their homes.
It is the first part of more than £1m in aid promised by Beijing, which is Pyongyang's oldest ally.
Foreign aid workers who were allowed to visit the blast site on Saturday said they found a scene of utter devastation.
The damage to buildings and infrastructure was huge and a long-term programme of international assistance would be needed to get the town back on its feet.
The delegation, which included representatives of UN agencies and several ambassadors, said they had been surprised by the degree of openness shown by the North Korean authorities at the site.
But Red Cross spokesman in Beijing, John Sparrow, said more visits would be needed to assess the full extent of support needed for those affected by the blast.
He told BBC News Online that homelessness had not been an issue in the immediate aftermath, as many of those whose houses had been destroyed had been taken in by others.
But he said agencies wanted to get reconstruction under way as quickly as possible, before the start of winter in October.
Hundreds of buildings were destroyed by the explosion
Mr Sparrow said he was confident local hospitals had enough supplies to treat the wounded in the short term, although they would soon need replenishing.
The BBC's Louisa Lim, in the border town of Dangdong, said the first trucks of Chinese aid cross into North Korea on Sunday.
She said food included instant noodles, tins and biscuits. Banners on the side of trucks said the goods had been donated by the government on behalf of the People's Republic of China.
In an unusually frank statement, North Korea blamed the disaster on "human error", saying rail wagons loaded with oil and chemicals ignited after coming into contact with power cables.
Buildings - including a hospital, college and school - in an area of several hundred metres were totally flattened, said foreign officials visiting the scene.
Mr Sparrow said on Sunday that the official death toll had risen to 161, including 76 schoolchildren.
China and South Korea have each promised about $1m in emergency aid to their neighbour.
Several other countries, including the UK, have also offered aid.
The United States, which has described North Korea as part of the "axis of evil" with Iran and pre-war Iraq, said it was willing to help with the disaster relief if asked.
The BBC's Jonathan Head in Seoul says the readiness of North Korea's communist authorities to seek international help has surprised most observers.
Some diplomats believe it offers a rare opportunity to build friendlier ties with Pyongyang and coax it towards greater openness.
British ambassador to North Korea, David Slinn - who was among those who visited Ryongchon on Saturday - told BBC News 24: "Anything that builds trust between the North Korean authorities and the international community has got to be a good thing."
Others are more sceptical, says our correspondent, believing it to be a continuation of North Korea's strategy over its nuclear weapons programme - trying to divide international opinion by encouraging some countries to believe constructive engagement is more effective than isolation.