The US has pledged to join United Nations relief efforts to help North Korean after last week's blast tragedy.
Officials say many of the children have horrific injuries
Secretary of State Colin Powell said money and supplies could be provided, though he gave no details.
A UN aid official warned that North Koreans may suffer after-effects from the huge chemical explosion for years.
A massive blast tore through the town of Ryongchon on Thursday, leaving more than 160 dead and 1,300 injured. Many of the wounded are children.
Mr Powell said on Monday: "America has always been a giving nation that will respond in time of need."
State department officials say there has been no decision yet on the amount or type of aid to be offered to the country President Bush once described as part of an "axis of evil".
China and South Korea have each promised $1m in aid to their neighbour.
While help is now being sent to the site of the blast near the Chinese border to cope with immediate needs, Eigil Sorenson, head of the World Health Organization's office in North Korea, said long-term issues needed to be addressed too.
One of the chemicals that exploded, ammonium nitrate, can lead to breathing problems and death, he said.
"Thousands could be affected," he told the French AFP news agency.
The Red Cross is seeking $1.2m in emergency aid to help as many as 10,000 victims.
The aid agency wants funds to provide food, clothes and cooking fuel following reports that North Korean emergency services are overwhelmed by victims.
The country is barely able to care for more than 1,000 people wounded in the explosion, roughly half of whom are children, aid officials say.
It has already used up a three-month supply of antibiotics, anaesthetics and bandages provided by the Red Cross at the weekend, the Associated Press news agency reported.
"According to the hospitals, they have already used these medical supplies
and have requested more," Niels Juel, a Red Cross official in Beijing, said.
International relief efforts have been hit by North Korea's refusal to allow South Korean aid supplies to cross the heavily guarded land border.
South Korean aid is now likely to reach North Korea by sea.
It will take up to two days to travel by sea - as opposed to four hours by land, the Red Cross said.
North Korea is notoriously sensitive about the area around the demilitarised zone (DMZ) which separates the two Koreas, and negotiating any changes to procedures there is rarely swift.
Aid workers allowed to visit the site describe scenes of total devastation in a 200-metre radius from the explosion with catastrophically injured patients being treated in the hospitals nearby.
A school located close to the tracks appears to have borne much of the force of the blast and children make up a disproportionate number of the injured at the Sinuiju Provincial Hospital.
Masood Hyder, a senior World Food Programme (WFP) official who visited the hospital, told the BBC: "Most the injuries are facial; many people have lost eyes. Some unfortunately have lost both eyes."
He said most of the injured, including many with burnt and gouged-out eyes, had been hit by hot air and burning grit from the explosion.
"If you were facing [the blast], you got it straight in the face," he said.
The disaster has given foreigners a rare inroad into the secretive state.
Workers at the local hospital were trying to cope with the disaster despite poor supplies but, said Mr Masood, "were freely admitting to us... they need everything".
Another WFP official, Tony Banbury, told Associated Press of how children were being treated atop filing cabinets at an overcrowded hospital.
"We saw children rolling and moaning in pain, many with a lot of cuts to the face and rudimentary twine stitching," he said.
North Korean officials say the blast happened when electric cables ignited explosive chemicals and oil that were being transported on a passing train.
CORRECTION: A photograph that appeared in some versions of our story N Korea train blast 'kills many', published on Friday 23 April, was published in error. We said the photograph was an image of smoke from fires burning at the site of the North Korean accident at Ryongchon station. It was not, and we apologise for the mistake.