The Israeli military says it has begun a ground offensive into the Gaza Strip.
The military issued a statement at 10:30 PM on Thursday announcing the launch of the operation.
Israeli Prime Minister Benjamin Netanyahu said in a statement he had instructed the military to commence ground action and blamed Hamas militants using a tunnel to infiltrate into Israel on Thursday.
It says in light of Hamas' relentless aggression as well as the dangerous attempt to infiltrate into Israeli territory, Israel must act to defend its citizens.
The Israeli military says the goal of the ground operation is to target Hamas' tunnels that cross under the Israel-Gaza border, enabling militants to enter Israel and carry out attacks.
Hamas has called the launch of the offensive a dangerous first step. The group warned of a high price for the action.
Details of the operation are not known.
An NHK reporter in Gaza says fierce attacks appear to be underway in eastern Gaza, and huge explosions can be heard in western Gaza.
Since Sunday, Israeli forces have been warning residents near the border between Gaza and Israel to evacuate.
Egypt had brokered a ceasefire, but no agreement has been reached as of Thursday.
This is the first Israeli ground operation in Gaza since 2009.
231 people, including many civilians, have been killed in the latest attacks on Gaza. More than 1,700 people have been wounded.
Jul. 18, 2014 - Updated 02:00 UTC