With rescuers running out of time in Soviet Armenia, relief efforts mounted throughout the world to help thousands of victims of this week's earthquake, which may have killed 80,000 people.

The U.S. government is chartering an airplane to send medical supplies and canine search teams to help the earthquake relief effort in Soviet Armenia, American and Russian officials announced Friday.

The U.S. government offered to help Thursday but received no response until late Friday afternoon when Yevgeny Kutovoi, minister-counselor in the Soviet Union, met at the State Department with Julia V. Taft, the head of the U.S. Agency for International Aid Office of Foreign Disaster Assistance.

"We don't even have a plane yet," said Cindy Stuart, a spokeswoman for the office. "The teams and goods are being assembled right now." The places and times of departure and landing had not been determined yet, she said.

Firefighters said they pulled about 80 people out of the crumbed buildings in Len-inakan _ Armenia's second-largest city _ and Tass said 200 people were pulled out of debris at a factory on Thursday night.

"In these conditions, delaying by each hour means an additional 20 killed of every thousand concealed under debris. Such is the terrifying arithmetic," Health Minister Yev-geny I. Chazov told the newspaper Izvestia.

Survivors recalled screams, crashing ceilings and then total darkness as they were buried in rubble, the newspaper Izvestia said on Friday. In the first harrowing accounts by survivors published in the Soviet press, the newspaper Izvestia said many people did not take the quake seriously when it first struck just before noon.

"At the first tremor, my girlfriend and I started laughing," said Sofia Nadoyan, who was buried for 24 hours in rubble before being rescued.

"Then suddenly the building crashed," she told the newspaper. "It was dark and I was lying under the fragments. I didn't know in which world I was, still here or already there."

Her friend's fate was unknown.

A man from the town of Spitak, which was completely leveled by the quake, said he fell four floors before being buried alive. Kamil Yumaev said he was rescued after about an hour and taken by helicopter to a hospital.

Izvestia said not all those who initially survived the quake had continued to live. It said 90 people brought to hospital in Yerevan had died.

One survivor interviewed by the newspaper, Ruzanna Grigoryan of Leninakan, said she now was having nightmares about crawling after spending four hours in total darkness, trying to extricate herself from debris.

At first, she said, "I did not notice anything myself. Then I heard someone crying, `Earthquake!' In the next moment everything crashed . . . I noticed the ceiling was falling."

The news agency Tass said there may still be people alive under the debris of the quake, which struck at midmorning Wednesday when schools and factories were full.

Soviet TV showed rescuers combing crumbled buildings, carefully removing blocks of concrete in a search for survivors. A correspondent said the workers could hear voices from below.

"Somewhere here is my brother," said a mustachioed man standing in the debris. "He worked as a factory director. He came home during a break and stayed here. Children are here . . . and father, they just took him away. They took him to his funeral."

Smoke wafted from the rubble and the man added in a hoarse voice to the television interviewer: "I don't know, maybe they (the children) already burned up here because we haven't been able to extinguish this fire for several days. Oh, the grief is terrible!'

Government spokesman Lev Vos-nesensky said the number of dead was certain to rise. "We already have people screaming from beneath the ruins. Every hour these screams get quieter."

He said the rubble itself posed the biggest problem for rescue workers who were suffering a chronic shortage of heavy lifting equipment.

Tass said that only after the rubble was cleared, rescue work was completed and the dead buried could mass evacuation start from the cities and villages affected by the quake and rebuilding begin in earnest.

The Soviet Union's allies and ideological adversaries offered help.

France dispatched planes to Yerevan carrying doctors, search dogs and medical supplies; Switzerland dispatched rescuers and more dogs; Britain pledged $9.3 million in aid and helped with specially trained firefighters.

The American Red Cross collected money, antibiotics and supplies, and the Soviet Embassy in Washington said it has been overwhelmed with telephone calls and by people who are "walking up to the doors of the embassy with checks and money orders."

In the heavily Armenian community in Watertown, Mass., donations of money, clothing and offers of help poured into the St. James Apostolic Armenian Church community center.

A plane of supplies from Bulgaria landed in Armenia on Friday. The Polish government pledged tents, sleeping bags, bandages and medicine. Factory workers donated money.

Muscovites donated money at their workplaces, and 12,000 volunteers worked on disaster relief in the Armenian capital, Yerevan.

"The main thing is blood. We need transfusion blood," said Igor Deni-sov, deputy health minister. Supplies of blood were sent in from Finland, France, Sweden and Norway.