The Islamist Hamas movement praised Gaza's "steadfastness" as the battered enclave marked Sunday the first anniversary of the deadliest Israeli offensive ever launched against the territory.

Anniversary events began with sirens sounding at 11:20 am (0920 GMT), when the first bombs of Israel's "Operation Cast Lead," launched in a bid to halt years of rocket fire from the enclave, slammed into the coastal strip.

The wave of air raids launched on Hamas targets across Gaza on December 27, 2008 killed at least 225 people in what was one of the bloodiest single days in the decades-long Israeli-Palestinian conflict.

"The enemy wanted with this bloody surprise to shock the people of Gaza and the government and the resistance, but faith in God was stronger than the shock and the planes," Hamas leader Ismail Haniya said in a televised address.

"Gaza was victorious with its legendary steadfastness," the prime minister in the Hamas-run government added. "It was victorious when Israel, the enemy, failed in all its war aims."

North of Gaza City, hundreds of people carried pictures of the fallen past a UN school hit during the war and the destroyed home of Nizar Rayan, a senior Hamas leader killed in an air strike along with his four wives and 10 children.

Israel did not observe the anniversary, and Prime Minister Benjamin Netanyahu did not mention the war during a weekly cabinet meeting.

'Dark days'

When the 22 days of fighting ended on January 18 with mutual ceasefires by Israel and Hamas, some 1,400 Palestinians, including more than 400 minors, and 13 Israelis had been killed. Another 5,500 people were wounded in the fighting.

"Those were dark days. There was killing in every street and alley," said Dr Muawiya Hassanein, the head of Gaza emergency services. Sixteen of his paramedics were killed as they struggled to collect the wounded.

The end of the war ushered in the calmest period along Gaza's borders in years, and the number of Palestinian rocket attacks in the year since the war has been 90 percent less than the one preceding it.

But Hamas remains firmly in power in Gaza and sworn to the eventual destruction of Israel, and both sides are believed to be busily preparing for the next round of bloodshed.

"We are developing our capacities to match the Zionist escalation, and it is our right as the Palestinian resistance to develop and acquire whatever weapons we can," Abu Obeida, a spokesman for the armed wing of Hamas, told reporters.

"We are ready to confront any new aggression with all our power," he added.

Israel has come under intense criticism from the international community and human rights groups who have accused it of disproportionate force during the operation, including the use of white phosphorus in residential areas.

It has also faced criticism for punishing sanctions imposed on Gaza since Hamas seized power in June 2007 that have prevented almost any reconstruction from taking place. Egypt has also largely sealed its border with Gaza.

War crimes

A UN Human Rights Council report released several months ago accused both Israel and Palestinian militants of committing war crimes during the offensive.

The war and the blockade have also drawn criticism from the Western-backed Palestinian Authority, with moderate president Mahmud Abbas on Sunday vowing to pursue Israeli "war criminals."

UN Secretary-General Ban Ki-moon warned that "neither the issues that led to this conflict nor its worrying aftermath are being addressed."

"There is a sense of hopelessness in Gaza today for 1.5 million Palestinians, half of whom are under 18. Their fate and the well-being of Israelis are intimately connected," he added.

Some 6,400 homes were severely damaged or destroyed during the war, according to UN figures, as well as several large factories and farms.

Most of the tens of thousands of people who lost homes now share crowded apartments with relatives or huddle under tents supplied by aid groups, and the UN Relief and Works Agency for Palestine refugees (UNRWA) has started building homes out of mud bricks because of the shortage of concrete.

"Gaza has been bombed back to the mud age, not the stone age," UNRWA spokesman Chris Gunness said.

- AFP