COLOMBO, Sri Lanka — Sri Lanka’s army disbanded the mostly ineffective “safe zone” it had established in the war-wracked north and set up a new refuge today for the tens of thousands of civilians still trapped.

Military spokesman Brig. Udaya Nanayakkara said the government set up a new haven because the Tamil Tiger rebels forced most of the civilians seeking shelter from the fighting out of the original one.

The two sides have been fighting heavy battles since government troops overran the rebels’ de facto state in the north and boxed them into a tiny strip of land along the northeast coast. The military says it has pushed the insurgents to the brink of defeat and hopes to soon end the 25-year-old civil war.

Aid groups estimate that about 200,000 civilians are trapped in the war zone. The government says the figure is about half that number.

The government established the first safe area Jan. 21 in a small patch of land inside rebel-held territory. Security forces encouraged families trapped in the war zone to move to the refuge and pledged not to attack that area.

However, rebels, health officials and other observers said the zone came under almost immediate artillery shelling, at least some of it from the government side.

An internal U.N. memo said some of its staff members and their relatives who sought shelter in the area where forced to relocate out of the “safe zone” because it had grown so dangerous.

The government has denied attacking the area.

Over the past week, tens of thousands of civilians fled from the refuge into the neighboring government-controlled areas to the west, but the flow has slowed considerably over the past day.

The military said the rebels, known as the Liberation Tigers of Tamil Eelam, forced the civilians there to move to the east, toward the coast. The military has accused the rebels of holding the civilians hostage to use as human shields against the government offensive, an accusation backed up by several wounded patients evacuated from the area.

“The original safe zone, the people have already come to the area where the security forces are, and all the others have been removed forcefully by the LTTE,” said Nanayakkara.

The new refuge established by the government would consist of a 7.5-mile-long (12-kilometer-long) strip of land along the northeast coast where many of the civilians already were seeking shelter, Nanayakkara said.

On today, the Red Cross sent a ferry on a second trip into the war zone to evacuate scores of wounded civilians trapped in a coastal school being used as a makeshift hospital. The ferry also brought 240 patients to the town of Trincomalee inside government-controlled territory Tuesday.

Meanwhile, troops advanced further into the rebels’ shrinking stronghold today, capturing a rebel factory in the village of Sugandirpuram, where the insurgents transformed 81mm mortar shells into roadside bombs, Nanayakkara said.

On Wednesday, troops and rebel forces fought at least seven battles across the war zone, with both sides sustaining damage, the military said.

Confirmation of the fighting was not available because independent journalists were barred from the war zone.

The Tamil Tigers have been fighting since 1983 for an independent state for minority Tamils, who were marginalized for decades by successive governments controlled by the Sinhalese majority. More than 70,000 have been killed in the fighting.