Gaza. More than 100 Palestinians are said to have been killed after Israel intensified its bombardment of Gaza and warned of a long conflict ahead.

Gaza’s only power plant caught fire as Israel carried out 60 air strikes, targeting sites associated with Hamas, the Islamist group which controls Gaza.

UN staff members are said to be among those killed.

An Israeli military spokesman said the strikes signalled a "gradual increase in the pressure” on Hamas.

Power plant destroyed

Gazans get power from just one local plant, as well as some supplies from Israel and Egypt.

On Tuesday morning a huge plume of smoke rose over the strip’s only power plant after one of its fuel tanks was reportedly set alight by Israeli tank shells, and the facility was forced to shut down.

For the last three weeks, most Gazans have been living with just a few hours of electrical supplies - now the situation will almost certainly get worse.

After a brief lull in the fighting earlier this week, the violence has returned with a renewed intensity.

In Gaza City you can hear the constant bombardment of areas close to the Israeli border. There have also been large explosions in the city throughout the morning.

Any sign that a patchwork of truces would lead to more a sustainable ceasefire has been dashed for now. More than three weeks on there is in general very widespread support among Israelis for the Gaza offensive. Recent polls say almost 90% of Israelis are in favour.

Some are beginning to ask whether the army and the government underestimated the tunnel threat from Gaza. Targeting the tunnels is one of Israel’s main objectives in this campaign, but destroying them is complicated.

Israel says it has identified more than 30 tunnels - but the army was taken off guard last night when five soldiers were killed by Palestinian militants who came up through a tunnel into Israel.

Military sources say these aren’t just single shafts but a labyrinth of underground passageways, some booby-trapped with explosives.

The government says it will not stop the offensive until the tunnels are destroyed.