Israel must act in a "proportionate" way in its actions in Gaza but has the right to defend itself, Foreign Secretary Philip Hammond said.
He added Britain "will be looking very carefully" to make sure that civilians are being protected as Israeli troops continued their offensive.
Speaking on The Andrew Marr Show he said: "Israel has a right to defend itself against these rocket attacks coming from Gaza, but it must do so in a way that is proportionate and it must take all measures necessary to prevent unnecessary loss of civilian life."
Mr Hammond said the international community was trying to "stop the bloodshed, re-impose a ceasefire and then find a longer-term solution" to ensure conflict does not flare up every few years.
In between the bandages, I could see the soreness of Randa’s skin. Her eyes stare out at a world which has been brutal to her.
An Israeli student has started an online campaign in an attempt to encourage respect between Jews and Arabs.
A BBC Arabic reporter was set upon by an angry Israeli bystander in the middle of a live broadcast on the situation in Gaza.