Aid agencies are trying to gather an accurate picture of the number of people displaced from their homes by the conflict in Lebanon. But assessing the true number of people likely to need humanitarian assistance is so far proving virtually impossible.

Aid groups say hundreds thousands of people could have been displaced by the fighting already. But, in reality, the true figure is still unknown.

The first estimates range from 100,000 to more than half a million.

Aid workers are relying on the news media and contacts on the ground to try to draw up an accurate picture of how many people will need help in the days and weeks ahead. But since it's still impossible to reach many parts of Lebanon -- particularly in the south -- it may be some days before the situation becomes clearer.

But already, reports of large groups of displaced people gathering in schools, mosques and other centres are beginning to filter through. Food and water stocks are low and there are concerns that they could soon succumb to illness unless they're helped soon.

I spoke to a spokesman from the International committee of the Red Cross this afternoon and he said he was increasingly concerned at the infornmation he was receiving.

Aid groups are preparing to mount a major humanitarian operation if it becomes necessary. They’re organising supplies of food, clothing and medical equipment which can be deployed quickly to the most needy people.

The concern is that the number of those vulnerable people could be growing by the day.