Amid the pomp and piousness of their Orthodox Holy Week observances, this city's large Ukrainian community is frustrated and angry over Soviet handling of the nuclear power plant explosion near Kiev, where many have relatives living.

With community leaders reporting telephone service between the United States and the Ukraine is almost nonexistent, fears about the accident's danger continue, despite Soviet assurances that the crisis is abating.

"We are very much upset, because they the Soviets tried to keep silent about it," said Emil Basiuk, who with hundreds of other Ukrainians attended an ecumenical prayer vigil at Daley Plaza outside City Hall today.

"It is inhuman how they treat people," said Basiuk, director of the Ukrainian National Museum. "We're very glad that now, people outside the Soviet Union have had their eyes opened and see for themselves that they cannot believe what the Soviets say."

Many of those attending today's vigil came from the heart of the Ukrainian Village, the West Side community centered on Chicago Avenue, west of the Loop where many of the estimated 75,000 Ukrainian emigres live.

The vigil included gestures of solidarity from Ukrainian Orthodox, Ukrainian Catholic, and Protestant congregations, and several aldermen said they will submit a resolution offering Chicago's humanitarian assistance to all nations affected by the possible fallout.

"Almost every older Ukrainian in the Chicago area would have relatives in the Ukraine," said the Rev. Olexa R. Harbuziuk, pastor of the Ukrainian Baptist Church, in the southwestern suburb of Berwyn.

In a telephone call after the vigil, Harbuziuk said, "I just talked with a friend who has friends there who are begging, asking, 'Tell us what happened. Would you tell us?' "

But, community members here noted, little information is coming from the Ukraine. Said Basiuk, "Someone talked to his sister who lives near Kiev and she told him, 'We haven't been told how to behave.' "

"The Soviet government always suppresses all information from their people," Harbuziuk said. "Other countries started to talk about the tragedy, and they had to say something to their own people, but they didn't say much. They definitely did not tell the truth about the tragedy that happened in the Ukraine."

At the Ukrainian-American Club on West Chicago Avenue, a member said, "There are people here with relatives there, sure. But nobody wants to talk to you about it."

At the Ukrainian Uniate Catholic Church of St. Volovymyr and Olha, the Rev. Peter Galadza said he expects about 4,000 persons at the blessing of Easter food on Saturday.

"Easter celebrations are very important," he said. "Especially now."Special correspondent Laurie Kalmanson contributed to this report.