Israel bombarded dozens of targets in the Gaza Strip on Tuesday, stepping up what it said might become a long-term offensive against Islamist Hamas after a surge in Palestinian rocket attacks on Israeli towns.
Following the worst outbreak of violence along the Gaza frontier since an eight-day war in 2012, the Israeli military said a ground invasion of the enclave was possible, though not imminent, and urged citizens within a range of 40 km (24 miles) of the coastal territory to stay close to bomb shelters.
"We are preparing for a battle against Hamas which will not end within a few days," Defence Minister Moshe Yaalon said in a statement.
"We will not tolerate missiles being fired at Israeli towns and we are prepared to extend the operations with all means at our disposal in order to keep hitting Hamas."
A source in Prime Minister Benjamin Netanyahu's office quoted the Israeli leader as saying: "The IDF (Israel Defense Forces) must be ready to go all the way. All options are on the table, including a ground invasion."
The Israel-Gaza border heated up last month after Israel's arrest of hundreds of Hamas activists in the occupied West Bank, where three Israeli youths went missing on June 12.
More than 200 rockets have been launched at Israel from the Gaza Strip, the military said, since Israel mounted the dragnet while searching for the teens, who were found dead last week.
Israel has accused Hamas militants of killing them. In a suspected revenge attack, a Palestinian teen was abducted in East Jerusalem last Wednesday. His charred body was found in a forest and six Israeli suspects have been arrested.
In the Gaza fighting, a Hamas fighter was killed in an air strike in Nusseirat refugee camp, Palestinian medical officials said. Palestinian officials said targets included militants' training facilities while six homes were bombed in the Gaza Strip and 30 people were also wounded.
The Israeli military said that in the past 24 hours, more than 100 rockets had been fired at Israel, a sharp increase. Some were intercepted by the Iron Dome anti-missile system, but two people were wounded by shrapnel.
Some 1,500 Israeli reservists had been mobilised and more could be called up, the military said.