A deceptive summer truce between Dutch and Moluccan communities was shattered by arson and gunfire here today as the trial of seven Moluccans charged with terrorist kidnappings in May continued.

Moluccans youths set two schools and a Red Cross center ablaze last night, aggravating racial tensions in this province in Northern Holland. A policeman was shot in the stomach during an exchange of gunfire. His condition was described as satisfactory.

Armored cars were on duty and sandbags were piled up at strategic points to protect police.

Firemen retreated when Moluccan gunmen opened fire on them, but resumed firefighting at dawn under cover of an armored vehicle. The schools were gutted, but the Red Cross building was only slightly damaged.

Six Moluccans were arrested, and a Dutchman with a carbine was detained in an apartment house.

The hostilities were a grim reminder that Moluccan militants have lost none of their zeal since two bands of them seized more than a hundred school children and hijacked a train on May 23.

After four days of the dual siege of a school building and the train the children were released unharmed, but four teachers and about 50 passengers were held captive 20 days before marines freed them in an attack in which hostages and six gunmen were killed.

"Nothing has changed since then . . . nothing," an embittered young Moluccan told a reporter. "The Dutch government still won't help us get out islands back so we have to do it ourselves."

The terrorist actions caused deep divisions among the 40,000 Moluccans in the Netherlands, pitting parents against sons and daughters who advocate the use of violent tactics to regain their homeland - some 150 islands in eastern Indonesia.

Radical Moluccan youths scorn the Dutch government for trying to assimilate them now after failing to carry out a promise of repatriation. Almost 30 years ago, 12,000 Moluccans were forcibly shipped to Holland, but, out of gratitude for their service during colonialist wars, the Dutch government promised that one day they could return to set up an independent republic.

Frustrated by their unfulfilled dream, Moluccan militants have become alientated from the leaders of the South Moluccan government-in-exile here. Many young Moluccans are disdainful of President Johannes Manusama, whose meek diplomacy in seeking to create a Moluccan republic has proved fruitless, they say.

"The only thing which we agree with him on is getting our homeland back," Fred Tumuhuri, a Moluccan youth leader in Assen, said. "But we youth people feel all methods are justified."

Many young Moluccans revere the dead gunmen as martyrs and have maintained a vigil for the surviving terrorists on trial inside the barricaded courthouse.

When the trial opened Tuesday, several groups of young Moluccans held banners with ominous messages, one read: "Our Revenge Will Come at the Moment When You Are Sleeping." Another said: "It Is Better to Be a Terrorist Than a Fascist."

The seven gunmen on trial, who range in age from 18 to 28, are charged with "illegal deprivation of liberty and illegal possession of arms." If convicted, they could be sentenced to up to nine years in jail. A verdict is expected in two weeks.

Most observers believe that the terrorists will receive relatively light sentences - perhaps four to five years in prison - chiefly because their statements that they did not intend to kill have been corroborated by several hostages.

Willem Soplanit, the avowed leader of the group that seized the village school, asserted in court that "the guns were used only as a threat" and that the terrorists agreed in advance that they would not kill any hostages.

However, one of the gunmen who had been on train testified that when the marines attacked, he raced into the compartment where women hostages were sleeping, determined "to shoot everybody," but lost his courage.

The gunmen said that the Dutch government had betrayed them by promising to fly them out of the country once the children were freed. When all of the pupils had been released, the gunmen said, they began collecting their belongings only to learn that the government had reneged on the deal, insisting upon being told their destination.

The state's negotiator during the siege, Dr. Dick Mulder, a psychiatrist, testified that he made no promises and surmised that the gunmen "misunderstood" his proposals.

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