NEVE DEKALIM, Gaza Strip (Reuters) - Israel launched its Gaza pullout on Monday, sending police and soldiers to deliver 48-hour eviction notices in Jewish settlements where hundreds of hardliners blocked gates and vowed resistance.

The army sealed off the occupied territory overnight and began deploying after daybreak to tell Gaza settlers they must leave by Wednesday or be forcibly removed under Prime Minister Ariel Sharon's "disengagement plan."

But troops mostly held back as defiant settlers, some swaying in prayer, used makeshift barricades and their bodies in a bid to prevent an operation paving the way for Israel's first uprooting of settlements on land Palestinians want for a state.

"A lot of blood was spilled on this holy land," said settler Chaim Gross in the Morag enclave. "It was presented to Abraham for the Jews and we are not going to leave it."

Eviction warnings to 9,000 settlers in all 21 settlements in Gaza and four of 120 in the West Bank went into effect at midnight on Sunday, setting the stage for one of the most divisive chapters in the Jewish state's history.

The pullout to end Israel's 38-year occupation of Gaza, claimed by Palestinian militants as a victory and decried by Israeli opponents as a surrender to violence, is seen by Washington as a possible catalyst for renewed peacemaking.

Under floodlights after midnight at the Kissufim Crossing on the Gaza border leading to the Gush Katif settlement bloc, the army lowered a gate with a red sign that declared: "Stop. Entry into the Gaza Strip and presence there is forbidden by law!"

SOME SETTLERS STREAM OUT

Along a side road, a constant stream of settlers and trucks loaded with belongings left the Gaza settlements to comply with Sharon's plan to "disengage" from conflict with Palestinians.

Heading in the opposite direction, convoys of military vehicles, ambulances and buses drove into the Gaza Strip.

By rare agreement with Israel, 7,500 Palestinian security men in Gaza moved into position on the outskirts of the fortified settlements to ward off possible militant attacks.

Early on Monday one makeshift rocket slammed into the Neve Dekalim settlement and another hit Gadid, causing no casualties. Palestinian militants have largely observed a truce agreed by Palestinian President Mahmoud Abbas and Israel in February.

Troops planned to fan out in the settlements during the day to issue eviction notices.

But in an apparent bid to avoid early confrontations, the army said it had decided not to go into five of the settlements, widely seen as bastions of resistance, until evacuation day after settlers said the soldiers would not be welcome.

Several hundred settlers stood at the gates of Neve Dekalim, the largest Gaza enclave, where tires and coils of razor wire blocked the road. But troops swept in without opposition to the more secular settlement of Nissanit, already largely abandoned.

"We estimate that no more than 50 percent of the residents of Gush Katif and (the other settlement areas) in the Gaza Strip will remain beyond the 16th," Brigadier-General Guy Tzur, who oversaw the Kissufim closure, told reporters.

STATE COMPENSATION DEALS

Hundreds of Gaza settlers have signed state compensation deals to leave, but the army said 5,000 pullout opponents had slipped into the enclaves, raising fears of violence.

Under the slogan "Jews don't expel Jews," settler leaders have been waging an emotional campaign against Sharon's plan to uproot settlements he said had little security value for Israel.

Palestinians welcome Israel's withdrawal from land captured in the 1967 Middle East war. But they fear Sharon devised the Gaza plan as a ruse to cement Israel's hold on most of the West Bank, where 230,000 settlers and 2.4 million Palestinians live.

The World Court describes Israeli settlements as illegal. Israel disputes this.

Israel intends to leave the Gaza settlements and the four isolated enclaves in the West Bank by September 4. It plans to complete the Gaza pullout in October, when the last Israeli troops are scheduled to leave.

But, citing security concerns, it plans to retain control of Gaza's airspace and possibly its border crossings.

U.S.-led mediators hope the pullout, which opinion polls show a majority of Israelis favor, will breathe new life into a "road map" peace plan.

Under a deal with the Palestinians, Israel will demolish the settlers' homes. The Palestinian Authority wants to build high-rise housing on the plots to improve conditions in densely populated Gaza, where some 1.4 million Palestinians live.