By Alan Johnston
BBC correspondent in Gaza
The Israeli military say they caught a group of Palestinians trying to dig a tunnel from the Gaza Strip into neighbouring Egyptian territory.
Israel has discovered 11 tunnels so far this year
The operation by the army was part of an ongoing campaign that Israel wages against tunnel diggers at the southern end of the Strip.
In this latest night raid the soldiers managed to catch eight men shovelling their way towards Egypt.
The aim is to prevent the smuggling of weapons to Palestinian militant groups.
Along the southern edge of the Rafah refugee camp you can see into Egypt.
At one point an Egyptian flag drifts in the breeze less than a kilometre away.
To try to cross the open ground, though, would be deadly - Israeli army tanks and jeeps patrol between the watch-towers.
But some Palestinians choose to go underground.
The Israeli army has discovered 11 tunnels so far this year.
It is gruelling and dangerous work. The army says some tunnels run for more than a kilometre.
They are deep, six metres or more, and there is always the risk of a collapse when an Israeli tank goes rumbling overhead.
But sometimes the end product can be substantial.
In Rafah they tell you of one tunnel years ago that was big enough to get a donkey cart through.
And the Israeli army says that the tunnels are getting more sophisticated. Some have communication links and electrified carts running on rails.
There is no doubt that they are used to smuggle weapons in for the Palestinian militants and that is why the army tries to hunt down every tunnel.
And if one is found beneath a house, it is always demolished. Many Rafah homes have been smashed.
But by no means all the diggers are linked to the militants.
The tunnels are often used by smugglers. Cigarettes, tobacco and even caged birds are sometimes brought into the Strip via the underground route.