Sri Lanka faces a "serious humanitarian crisis" and there is an urgent need to halt fighting at least briefly to rescue people in the war zone, according to the international Red Cross.
There was also not enough food and medicines for the large mass of civilians in the conflict area, said Paul Castella, who heads the International Committee of the Red Cross (ICRC) in Sri Lanka.
In an interview, Castella, 46, said the dominant worry for aid agencies was the unending civilian deaths in fighting between the Liberation Tigers of Tamil Eelam (LTTE) and the military.
"The main issue is one of security, protection. When we go there (war ravaged area), people tell us: 'Please protect us. Food is fine, but we need protection'," said Castella, who visited New Delhi and Chennai this week.
The ICRC, the only international agency active in Sri Lanka's north, has rescued around 4,000 civilians, mostly those wounded in fighting, since the start of February from Mullaitivu district. It wants to speed up the process.
"We talk to both parties expressing our concerns. Unfortunately, our discussions have not been as successful as we would have hoped. People are being killed every day. (There is) a very serious humanitarian crisis."
The military is desperately trying to overwhelm the last of the LTTE territory in a small area of Mullaitivu that is also home to a large Tamil population estimated at between 70,000 and over 200,000.
The LTTE has been accused of forcing the people to stay put to delay the military advances. The Tigers deny this and charge the military with killing civilians indiscriminately. Colombo denies this.
Castella explained how difficult and dangerous the situation was.
"We ask for a ceasefire of two to three hours to move people (from the conflict zone). One of the parties may have used this period to move troops and armaments. That triggers the other party to fire back.
"There is a lot of mistrust between them. It is very difficult to ask one side to stop firing when the other doesn't."
Castella, who has been in Sri Lanka since September 2008, acknowledged Colombo's role in providing health and other facilities for the civilians. But much more needed to be done.
"Food supplies are not enough. Both the government and the World Food Programme have contributed. Right now 500 tonnes are being unloaded, off Muallaitivu.
"It is good it has come. But food is very late, too little, and people are afraid to collect it (because of unending fighting)," he said.
The shortage of medical facilities to treat the civilian wounded was frustrating doctors and other medical staff. "One doctor told our staff: 'Just watching people die (due to lack of medicines) is useless'.
"The (Sri Lankan) health professionals are working in dangerous conditions, day and night. The doctors, the nurses... they are really very admirable."
Does he see any light at the end of the tunnel?
"The stakes are very high for both sides. The LTTE is fighting to survive. The government is trying to take control of the last of the territory the LTTE still has. Both sides are not ready for compromise. That is not helping," he said.
"Without safety, it is not easy to do humanitarian work."