A Palestinian militant has been killed during an assault on a Gaza settlement.
A Hamas member was killed in the first Israeli air strike since January
The Israeli army says the man was one of three attackers who fired anti-tank missiles and rifle rounds at the Jewish settlement from an abandoned house.
Israel has threatened tougher military action against Palestinian militants in Gaza if they continue a recent spate of attacks on settlements.
BBC Gaza correspondent Alan Johnston says the attack will put further strain on the fragile ceasefire in the area.
The three month-old truce is seen as a crucial element in the effort to restart the Middle East peace process.
The Palestinian assault on the settlement of Kfar Darom, in the centre of the Strip, began with a mortar attack before dawn.
The army says three militants took over a nearby abandoned building and opened fire into the settlement with six anti-tank missiles and light arms fire.
Mortars have been fired at Israel or at settlements
Troops shot back and killed one of the attackers but the others appear to have escaped.
There were no reports of casualties on the Israeli side.
Israel has called for the Palestinian Authority to act to stop such attacks.
"This continued indifference and inaction by the Palestinian Authority, which allows these terrorists to operate in broad daylight and under their very nose, allows these incidents to keep recurring," government spokesman David Baker said.
Our correspondent says that although militants on the Palestinian side have not formally endorsed the ceasefire agreed in February, they have reined themselves in and Gaza has been calmer in recent months.
However, violence escalated on Tuesday night when a Palestinian militant was killed in disputed circumstances in Rafah.
In retaliation, Hamas launched mortars at Israeli settlements in Gaza, triggering the first Israeli air strike since January.
On Thursday morning, three Qassam rockets were fired into southern Israel by members of the Hamas movement, but there were no injuries.
Palestinian Authority President Mahmoud Abbas has warned that the situation is so sensitive that "a very tiny spark" could trigger a major new round of violence.
Deputy Defence Minister Zeev Boim told Israeli public radio that Israel would "act in a more aggressive manner than we have so far".
Israel is planning to evacuate all its 21 settlements in the Gaza Strip and the troops who protect them as part of a unilateral disengagement plan.
It will maintain control of the borders, airspace and coastline of Gaza, which is home to about 1.5m Palestinians.