Croat Army Rolls On; Civilians Flee : Balkans: Tens of thousands of Croatian Serbs crowd roads as Zagreb continues its takeover of Krajina region. Death toll unknown, but abuses by victors are reported.

The Croatian army’s “Operation Storm” rammed through another rebel-held town Sunday, but its lightning victory over Serbs in the breakaway Krajina region was marred by reports of battlefield abuses and a colossal flight of civilians.

Overcoming stubborn Serbian resistance, Croatian armor and infantry captured the key town of Petrinja, 39 miles southeast of Zagreb. In central and southern parts of Krajina, mobile columns advancing along half a dozen lines encountered little opposition, U.N. analysts said.

“Krajina has ceased to exist,” Croatian Defense Ministry spokesman Maj. Gen. Ivan Tolj told reporters, building on an earlier affirmation that “Operation Storm is entering its end phase.”

Croatian Foreign Minister Mate Granic said Sunday that the fighting was nearly over. “We expect all major operations will finish tomorrow [Monday],” he told reporters after meeting with international mediators in Geneva.

Across this capital, checkerboard Croatian flags flew from buildings, and citizens boasted to each other of how quickly victory had come in a war Croatia launched at dawn Friday.

In the countryside, fleeing Serbs had a different point of view.

“Many dozens of thousands of people from Croatia are on the move in Bosnia,” said Vladimir Tsourko, head of U.N. relief operations in the Serb-held town of Banja Luka in northern Bosnia-Herzegovina. Serbian refugee agencies told U.N. officials that 120,000 people are on the road, but there was no independent confirmation.

Tsourko said the exodus could be the largest refugee flight in four years of war in the former Yugoslav federation. “The roads are all blocked by people and cars. It is impossible to count how many people there are,” he said.

In another disturbing development, a Croatian battalion attacking Serbs in northern Krajina used seven captured Danish peacekeepers and Serbian prisoners of war as human shields Friday and Saturday, the Danish government and the United Nations said in angry complaints Sunday. The soldiers were ultimately released unharmed.

Denying the accusation, Croatian spokesman Tolj said, “People want to diminish the brilliance of this military victory.”

In all, three U.N. soldiers have been killed and nearly a dozen wounded in the Croatian assault. About 65 U.N. observation posts have been destroyed and 350 blue-helmeted peacekeepers blocked or removed by attacking Croats, U.N. representatives said Sunday.

A Czech U.N. outpost was under attack Sunday afternoon, said Maj. Rita Le Cage of the United Nations. Typically, the Croats have removed the peacekeepers from battle areas and set them free, but about 80 soldiers were still unaccounted for Sunday, U.N. spokesman Chris Gunness said.

The United Nations won formal Croatian government agreement Sunday for access to Krajina to monitor human rights and offer humanitarian assistance, but the war areas remained closed to international officials.

Croatian authorities appealed for Serbian soldiers to surrender and for civilians to remain in their homes, promising that their rights as citizens of Croatia would be respected.

The Serbs weren’t listening. In a region where 10,000 people died in brutal fighting and many thousands of Croats were driven away in the wake of the 1991 Croatian Serb rebellion, this time the Serbs left their homes behind.

At least 35,000 people lurched in frightened convoys toward Serb-controlled areas of neighboring Bosnia on Sunday. The Bosnian Serb news agency SRNA said a column of refugees 12 miles long was streaming toward Serb-held territory from a mostly rural region in which an estimated 180,000 Serbs--a third of them soldiers--lived when the fighting began.

Diplomatic sources told reporters in Geneva that Croatia’s Granic had predicted that 99% of Krajina’s people would flee to Serb-held parts of Bosnia.

The United Nations said authorities in Banja Luka estimated that between 50,000 and 60,000 refugees would arrive in the next two days, and officials in the Serb-held Bosnian town of Prijedor said they were preparing to accommodate 15,000 in a soccer stadium. A U.N. spokesman warned of possible reprisals on minority communities of Croats and Muslims in Banja Luka.

About 10,000 Serbs huddled near a U.N. base in the Croatian town of Topusko, 60 miles south of Zagreb, which remained in Serbian hands. Among them were thousands of armed men with their families, their flight into Bosnia cut off by Croatian advances and those of allied Bosnian troops in the nearby Bihac pocket.

Five fires continued to burn out of control in the heart of Knin, the Krajina capital, which was hit by 2,000 shells Friday and captured by the Croats on Saturday. The commander of the U.N. garrison in Knin reported that there had been extensive looting, Gunness said.

“The situation in Knin is described as desperate,” the spokesman said.

About 700 civilians were sheltered at the U.N. base in Knin with 60 wounded civilians evacuated from Knin’s hospital after it was shelled. There was little food or water, the base commander said.

Croatian forces were not allowing peacekeepers to leave their base in Knin, Gunness said. One Canadian officer reported hearing sporadic shots from small arms, saying “it did not sound like combat.”

Gunness said the United Nations is “urgently demanding access to all towns, villages and rural areas affected by the fighting to address humanitarian problems and assess the human rights situation.”

No casualty figures were available Sunday, but Croatia acknowledged heavy losses in street fighting for Petrinja, an industrial city known for its food processing.

Before the Serbs’ 1991 uprising against Croatia, Petrinja had a population of about 35,000, split fairly evenly between Serbs and Croats. After six months of fighting that ended with a January, 1992, cease-fire, the Serbs had captured Krajina and expelled the Croats from the region. When the current fighting began, about 15,000 people lived in Petrinja. On Sunday, the city was deserted, smoking, in ruins.

“I would like to call on the [Serbian] rebels in the name of life and sanity to surrender. . . . Further resistance is insane. It has no political foundation or moral right,” Tolj told a news conference.

There was heavy shelling but little movement around the Croatian city of Karlovac to the northeast, where Croatian officers were trying to negotiate the surrender of 20 companies of Serbian tanks facing them across a narrow no-man’s-land.

The Bosnian government’s 5th Corps, pushing out of the Muslim enclave of Bihac, helped cut off retreat from the fighting, and Croatian sources said troops of a renegade Muslim warlord who had sided with the Krajina Serbs were surrendering in large numbers.

“We knew that we could liberate the occupied territories without provoking a wider conflict,” said Croatian President Franjo Tudjman in his first public comment on the weekend warfare.

The Krajina Serbs’ Bosnian allies did not offer significant support, and Serbia posed only a rhetorical challenge to Tudjman’s swift and successful weekend gamble.

Secretary of State Warren Christopher, interviewed from Vietnam on ABC-TV’s “This Week With David Brinkley,” said that Croatia’s military offensive against the rebel Serbs could have the positive effect of leading to a negotiated settlement to the regional conflict.

“We certainly didn’t want this to happen,” Christopher said of the massive Croatian assault against Serb-held areas of Croatia.

“But the facts may possibly give rise to a new strategic situation which could turn out to our advantage.”