Israeli Prime Minister Benjamin Netanyahu said his country had a "duty to take whatever action necessary" to defend the people of Southern Israel from rocket attacks from Gaza.
The Israeli military says Gaza militants launched 10 rockets into southern Israel today, though there have been no reported casualties.
Earlier today Israeli aircraft struck three militant sites across Gaza, it is not known yet if anyone was killed.
The EU's foreign policy chief, Baroness Catherine Ashton, has condemned the latest escalation of violence between Gaza and Israel reported today, and called for both sides to "refrain from escalating the situation."
Baroness Ashton reiterated her support for a two-state solution and the ongoing peace efforts by Egypt.
I am very concerned by the latest escalation of violence between Gaza and Israel. I condemn the firing of rockets and mortars into Israel, and call on both sides to refrain from exacerbating the situation.
Further regrettable loss of life and injury must be avoided. I support the mediation efforts by Egypt and reiterate that there is no place for violence in the Middle East. It is only through resumed negotiations that the legitimate aspirations of both Palestinians and Israelis will be met, through a two-state solution.
Foreign Secretary William Hague said he was very concerned about the violence in Gaza and southern Israel, and the reported death of a number of civilians. He called for "all sides to demonstrate restraint":
I am very concerned by the violence in Gaza and southern Israel, and the reported death of a number of civilians, including a child, in Gaza. I condemn the indiscriminate firing of over 100 rockets into Israel by Gaza-based militants. The UK supports the Egyptian Government in its efforts to achieve a ceasefire. All sides need to demonstrate restraint to prevent a dangerous escalation that would be in no one’s interests
Israeli President Shimon Peres has condemned the weekend rocket attacks by Gaza militants on southern Israel as "idiotic" and said Israel must respond "fully and immediately."
He was speaking before today's wave of attacks, which saw the back of a house destroyed in Netivot.
– President Shimon Peres, speaking to The Jerusalem Post
It’s the most idiotic shooting in the world, because if you shoot and you don’t know what you want to achieve, what’s the point? Do they want to destroy Israel? Do they want to make our lives miserable?
If they shoot, we have to respond fully and immediately. There is no room for any consideration.
The Israel military said Gaza militants have fired 110 rockets on southern Israel since Saturday, the Associated Press has reported.
They said 10 rockets had been fired by midday local time today, including one that struck the back of a house in Netivot.
Israeli aircraft struck three militant sites in Gaza earlier in the day, AP reported.
Israeli officials have warned of a tough response after a Palestinian rocket fired from the Gaza Strip struck a house in southern Israel.
The rocket hit the town of Netivot, causing damage but no injuries.
The strike ended a brief overnight lull to three days of clashes, which has left six Palestinians dead, including four civilians, and 40 wounded.
Eight Israelis have also been wounded in the cross-border attacks.