Elite Colombian troops flew into rebel territory Friday, the vanguard of an assault by thousands of soldiers aimed at retaking the zone after the president canceled peace talks.

The 200 soldiers flew into an abandoned army base early Friday aboard 10 U.S.-made Blackhawk helicopters. The soldiers — wearing night vision goggles and armed with assault rifles, heavy machine guns, rocket-propelled grenades and mortars — encountered little resistance as they arrived on the outskirts of the blacked-out town of San Vicente de Caguan, the largest town in the former rebel safe haven.

One soldier said the helicopters met some scattered automatic weapons fire as they approached the town, but none were hit.

Before the helicopters arrived at about 2 a.m., paratroopers dropped in the area, located about 175 miles south of the capital, Bogota, on the western side of the rebel territory.

The operation opened a government offensive to retake an area twice the size of New Jersey in southern Colombia that President Andres Pastrana ceded to the rebel Revolutionary Armed Forces of Colombia, known by its Spanish initials, FARC, in 1998 in an effort to promote peace talks.

Pastrana broke off peace talks Wednesday, angered by the guerrilla hijacking of a civilian airliner and the kidnapping of a senator, and ordered the military to reclaim the territory. The government blames the kidnapping on the FARC, which criticized Pastrana for calling off the talks, but did not deny responsibility for the hijacking.

To the east, about 1,000 infantrymen entered rebel-held areas, but were not entering towns because their objective is to pursue guerrillas, a senior army commander on condition of anonymity. No clashes or casualties were immediately reported.

Thousands more troops were expected within hours, as war planes continued bombing runs for a second day Friday against rebel implacements, Air Force spokeswoman Maj. Angela Rodriguez.

"It's great to be here and take over an area that is now part of Colombia again," Pvt. John Jairo Perez, one of the soldiers who arrived at the base, told a reporter.

In what was apparently its first statement since the offensive began Thursday, the FARC said it was willing to negotiate with "a future government that shows interest in retaking the road to a political solution to the social and armed conflict."

The statement, distributed to reporters in San Vicente by a messenger who said he'd been sent by the FARC, was signed by several rebel spokesmen. Its authenticity couldn't immediately be confirmed. Colombia elects a new president May 26. Pastrana is barred from seeking a second term.

Pastrana urged Washington to allow U.S. military aid destined for anti-drug operations to be used against the rebels.

Secretary of State Colin Powell said Friday that Pastrana had shown "enormous patience over a long period of time" in trying to bring rebels to the negotiating table.

"And he's been rebuffed. ... He finally felt he could go no further and he had a responsibility to the people of Colombia to protect them," Powell said. "We understand the decision he made. We support him."

As dawn broke, soldiers stood guard in a field blackened by a recent fire and patrolled the perimeter of the newly seized base. Others began patrolling a road leading into San Vicente, a town of about 22,000 people. Leftist rebels were known to be in the jungle and pasture surrounding the town.

Warplanes and assault helicopters flew nearly 400 sorties Thursday, bombarding guerrilla training camps, airstrips, roads, supply stations and drug laboratories, the air force said, while the government ordered 13,000 troops to advance on the rebel stronghold.

There were unconfirmed reports that the aerial bombardment hit the tiny hamlet of Rubi, causing civilian casualties. But Air Force chief Gen. Hector Velasco said the nearest airstrike to Rubi was 10 miles away.

Other unconfirmed reports said two air force planes had bombed the nearby village of La Ye, killing three civilians and wounding six. Armed Forces chief Gen. Fernando Tapias said the reports were being investigated — but warned they could also be rebel propaganda.

Pastrana ceded the safe zone to the FARC in November 1998 in an effort to bring the 16,000-strong rebel army to the negotiating table. The area is sparsely populated, with about 100,000 people.

In San Vicente del Caguan — where power went off before the troops landed at the nearby base — resident posted white flags at their homes to ward off attack from either side.

"The white flags symbolize peace. We don't want anything to happen," Amelia de Ficaro, 68, said Thursday.

Residents stripped six vehicles abandoned by the rebels along a road outside town. Also left behind was a sign that referred to U.S. anti-drug aid to Colombia. "The gringos give the arms. Colombia provides the dead," it said. Some 3,500 people are killed annually because of the war.

Also Thursday, a rebel in camouflage and brandishing an AK-47 rifle manned a checkpoint outside San Vicente del Caguan.

"We'll keep patrolling because this is Colombia and we're all over Colombia," he said.

On the road further outside the zone, an Associated Press team saw a 60-year-old woman get shot in the leg when a bullet fired by a FARC guerrilla ricocheted off a truck's tires. The rifle-toting rebel, who was trying to immobilize the truck to block traffic on the road, fled.

The FARC did not comment on the offensive. Phone lines to rebel headquarters were cut shortly after Pastrana announced he was calling off the peace talks.

Pastrana said he decided to act almost immediately after the hijacking, in which four armed guerrillas seized an Aires airliner and forced it down near the safe haven. A senator was kidnapped but 29 other passengers and crew were released unharmed.

Many Colombians rallied around Pastrana, whose peace policy had been highly unpopular.

"Colombia was generous with the guerrillas, but now there is no way to continue this process," Sabas Pretelt de la Vega, a top business leader,said Thursday.

Pastrana told reporters he still supports a negotiated solution but could not foresee more talks until the FARC demonstrates a sincere desire to achieve peace.

U.N. Secretary-General Kofi Annan offered his "good offices" to find a political solution and called on all forces to spare civilians. Amnesty International and Human Rights Watch urged the government to prevent right-wing paramilitaries from entering the zone and killing civilians suspected of collaborating with the rebels.

U.N. peace envoy James LeMoyne, who got the two sides to agree to cease-fire talks last month, expressed concern for the safety of residents in the zone.