Since Thursday 20 Palestinians have been killed in Israeli attacks in the Gaza Strip aimed at putting an end to rocket fire from the territory on southern Israel.

Since June 28 -- three days after an Israeli soldier was kidnapped by militants in an attack on an army post near the Gaza Strip -- the Israeli army has been pursuing its vast offensive to free him.

More than 220 Palestinians have been killed in the raids.

Two Israeli were slightly wounded late Friday when a rocket fired by Palestinian militants at the southern town of Sderot exploded.

The deaths bring to 5,434 the number of people killed since the September 2000 outbreak of the Palestinian uprising, most of them Palestinians, according to an AFP count.

"Hamas, which is reinforcing itself, constitutes a threat to Israel's security," Gilad said, referring to the Islamic militant movement which dominates the Palestinian government.

"Our priority is now to make it more and more difficult for the continuation of terrorism."

Israel says that militants in Gaza are amassing stockpiles of arms smuggled into the impoverished territory through tunnels from neighbouring Egypt.

According to army radio, General Yossi Baidatz, head of Israel's intelligence research department, told the weekly cabinet meeting Sunday that surface-to-air missiles and Russian-made anti-tank rockets had been brought into Gaza.

Defense Minister Amir Peretz already approved a first intensification of Israel's three-month-plus offensive in Gaza on Thursday after rocket fire from the territory hit his southern hometown of Sderot, wounding three people.

At least 22 Palestinians have since been killed and scores more wounded, as Israel pushed tanks and troops, backed by helicopters and drones, into more populated areas of the Gaza Strip.

In the most recent clashes, several dozen Israeli armored vehicles and bulldozers rolled two kilometres (more than a mile) into the northern Gaza town of Beit Hanun Saturday evening, closing off its southern entrance.

But Peretz said Israel needed to take further action to prevent Hamas stockpiling weapons as Shiite militant group Hezbollah did in Lebanon ahead of this summer's 34-day conflict.

"We've learned the lessons of Lebanon well," Israel's top-selling daily Yediot Aharonot quoted him as telling a closed-door meeting.

"We will operate against the armament immediately and we will not allow the terrorist organizations to become stronger. Israel is acting to prevent Hamas from joining the Iranian axis of evil."

Israel has not ruled out resuming control of the Gaza-Egypt border, the Palestinian territory's sole link with the outside world that bypasses the Jewish state.

The anti-smuggling efforts of the lightly armed Egyptian guards who currently patrol the border "could be significantly improved," Gilad said, although he refused to be drawn on any Israeli plans to replace them.

"We've learned from experience not to tackle such questions in public in order to preserve the element of surprise," he said.

Although the Israeli army insists that most of the 22 people killed since Thursday have been Palestinian militants, a 29-year-old woman was shot and killed by Israeli soldiers on Friday and three young children died in an air strike.

The army has said its offensive -- launched after the capture of a soldier in a deadly cross-border raid from Gaza in June -- is being conducted "against tunnels and other terror threats."

But a UN special envoy for human rights, John Dugard, has accused Israel of unleashing "collective punishment" in the territory, declaring last month that some 260 Palestinians had been killed and 800 wounded in the operation.

All told, 5,436 people -- most of them Palestinians -- have died since the Palestinian intifada resumed in 2000, according to an AFP count.

"We can be proud of the IDF's treatment of the Palestinians," reservist soldiers operating the center said. "It is a shame that the other side disrespects human life."

A tank and an armored personnel carrier brought in the latest arrestees around 11 am on Friday.

IDF sets up detention center near Gaza

The army said the latest wave of arrests in Gaza is part of intensified attempts to crack down on terror operatives implicated in firing Qassam rockets at Israel.

The army said arrest raid had been shelved since the pullout from Gaza in August 2005, but was dusted off with the kidnapping of Corporal Gilad Shalit on June 25 in a cross-border attack.

Detention center near Gaza

"Since yesterday, arrestees have been pouring in," a soldier told Ynet. "In the afternoon a number of Palestinians arrived, whose ages ranged from 15-year-old teenagers to adults aged 45. We made every effort to give the Palestinians a good feeling, we set up tables, benches, and we even set up shades so they don't have to stand in the sun."

Soldiers said the arrestees did not seem scared, and some were seen laughing. Most Palestinians who arrived at the center on Thursday were neither blindfolded nor handcuffed.

"Every one of them was taken to a tent for interrogation. Those with links to terror groups were taken by bus to another facility and the rest were released to Gaza within hours," soldiers said.

"We received orders to serve them hot meals, and the brigade set a table with bread and chocolate and served them drinks," reservists said. "We felt great pride for the treatment, for treating the Palestinians with respect, even those suspected of terror activities. It is sad that on the other side respect to human life in not as such, as they use children as human shields and an innocent population is under constant threat because of terror groups."