The heaviest exchange of fire between Israel and Gaza in months is drawing attention to Salafist groups in the Palestinian territory.
A group calling itself the Mujahedeen Shura Council says it has launched several rocket strikes on southern Israel since Tuesday. In the latest salvo, Israelis rushed to bomb shelters early Wednesday. Hours earlier, the Israeli military sent warplanes to attack militant targets in open areas of northern Gaza.
There have been no reports of casualties from the rocket fire or air strikes, the first Israel has launched since a November cease-fire with Hamas militants who control Gaza.
Israel said it offered medical care to Maysara Abu Hamdiyeh, who was serving a life sentence for attempted murder in a 2002 bomb plot against a Jerusalem cafe.
The Salafist group said the rocket attacks were in revenge for perceived Israeli mistreatment of a 64-year-old Palestinian prisoner who died of cancer on Tuesday.
Gaza is home to several Salafist Islamist groups whose members range from dozens to hundreds and share al-Qaida's belief in global jihad. They have carried out sporadic rocket fire on Israel for several years, sometimes in defiance of Gaza's Hamas rulers.
U.N. special coordinator for Middle East peace efforts Robert Serry said renewed violations of the November truce risk "unraveling the gradual, but tangible" security improvements in Gaza and southern Israel in recent months. Israel and Hamas agreed to the cease-fire under U.S. and Egyptian mediation, ending an eight-day war.
Israeli counter-terrorism analyst Boaz Ganor of IDC Herzliya said Gaza's Salafists remain small in manpower, but have strengthened their capabilities.
He said the Salafists took the lead in firing rockets at Israel in the weeks before the November war, prompting Hamas to join the salvos for the first time in years to avoid losing the spotlight to its smaller rivals.
"Those Salafists announced that they are going to establish a political party that will compete with Hamas in the next elections whenever they will be held in the Palestinian Authority," he said. "Hamas understood from that moment that if it will restrain itself and not take part in the clashes against Israel, it will pay in the ballot. I understand the whole situation in the recent months to be based on that understanding of Hamas, and the Salafist movements' success in the political arena in the neighboring Arab countries."
Hamas has insisted it abides by Egyptian-mediated cease-fire agreements and previously has called for all factions to do the same to safeguard the Palestinian national interest.
Ganor said Hamas used persuasion rather than force to prevent Salafists from launching rockets at Israel in the first three months of the truce.
A Gaza-based Hamas spokesman told Reuters Television Israel is to blame for the latest outbreak of hostilities. Sami Abu Zuhri accused Israel of "killing" the ailing prisoner and escalating the situation by carrying out the air strikes.
Israeli Defense Minister Moshe Yaalon says Israel will not tolerate "any sporadic fire" toward its citizens or forces. His warning also was in response to scattered mortar and gun fire from Syria into the Israeli-occupied Golan Heights.