Israeli forces have raided two synagogues in the Gaza Strip to remove hundreds of hardliners protesting against the removal of settlers.
Israeli troops are taking on the most defiant hardliners
Police faced strong resistance from activists who had barricaded themselves behind barbed wire in Kfar Darom.
On the second day of evictions in Gaza, troops also dragged protesters from the synagogue at nearby Neve Dekalim, the largest settlement in the territory.
Israel is withdrawing its settlers from Gaza, which it has held since 1967.
The confrontation at Kfar Darom was the most violent incident so far in the two-day-old operation to evict settlers from Gaza.
Kfar Darom is a small settlement in central Gaza, where resistance to the pullout has been particularly strong.
Unarmed police first entered the synagogue, where hundreds of protesters had been resisting eviction.
Riot troops then stormed the rooftop, where young protesters had remained behind coils of barbed wire.
The troops battled the activists who pelted them with sand, foam and liquid.
Several officers returned to the ground after acid was thrown at them.
Shouts and tears
Maj Gen Dan Harel, commander for the Gaza region, said he hoped to complete the evacuation of Kfar Darom by Friday.
"Understandings would be good - otherwise, we will move the people out anyway," he said.
Earlier, troops cleared the synagogue at Neve Dekalim.
The BBC's Richard Miron - who was inside the building - says there was a great deal of shouting and singing by the demonstrators as soldiers moved in.
But there was no violence as settlers and their supporters were carried out one by one, many of them screaming or crying.
Hardliners are also being taken away from the settlements of Shirat Hayam and Kfar Yam.
Police at Kfar Yam say they have ended a stand-off with an armed settler who had threatened to open fire on troops if they tried to remove him.
After talks, the settler promised not to use his weapon, officers said.
Israeli officials say the mission is going faster than expected and may be over within days, instead of the scheduled six weeks.
The army says about 70% of settlers have left or been removed.
Hold-outs in Kfar Darom took refuge in the synagogue
More than half of the 21 Gaza settlements were cleared on Wednesday, the first day of the operation. Some settlers burnt their homes as they left.
Also on Wednesday, a Jewish settler killed four Palestinians in the West Bank - an act condemned by Israeli Prime Minister Ariel Sharon and Palestinian leader Mahmoud Abbas.
A few hours later, Palestinian mortars were fired at a Jewish settlement in Gaza, but the Israeli army said there were no injuries.
Thousands of Palestinians in Gaza have been celebrating the withdrawal, which marks the first removal by Israel of settlements built on Palestinian land seized in the 1967 war.