A mysterious wave of poisonings has struck schools in the Afghan capital of Kabul, sending hundreds of schoolchildren to hospitals.

Kabul authorities acknowledged on state-run radio that 488 students suffered gas poisoning in at least seven schools yesterday. According to the official announcement, the entire staffs of some Kabul hospitals were kept busy treating the students while anxious parents pressed doctors for news of their children.

The announcement blamed "agents of American imperialism" and "Chinese chauvinists" for the attacks.

Some observers noted that students from the affected schools had been in the forefront of student demonstrations against the Babrak Karmal regime earlier this year, and speculated that the government had gassed the schools to punish and warn the youngsters. Others who believe that resistance elements are responsible say the rebels are punishing "progovernment" students for attending rather than boycotting their classes.

Some sources, while not discounting the incidents of gas attacks or contaminated food and water, suggest that mass hysteria may account for the large numbers of students involved.

Teen-agers, they point out, are believed to be especially susceptible to the phenomenon, in which the fears or disease symptoms of one or a few individuals quickly spread through a larger group.

Eyewitnesses, whose reports reached New Delhi today, reported seeing nearly 100 girls at the Rakhshana Elementary School -- not one of those mentioned in the radio accounts -- lying on the school grounds waiting for ambulances to take them to hospitals. The girls claimed that they had been poisoned.

Other reports told of 50 boys incapacitated at another school after drinking contaminated water offered by their teacher. By official accounts on Kabul Radio, one school, Soriya, was struck three days in a row, first by poisoned water and then by poisonous gas. The state-run radio also said 30 workers at a government printing plant were taken to hospitals after poisonous gas attacks.

In perhaps the strangest unconfirmed report, an elementary school principal, two teachers and three students were said to have been knocked unconscious by a sweet-smelling gas when the principal -- described as a government loyalist -- dropped a bottle of perfume in her office.

One informant said a similar poisoning outbreak occurred at three girls' schools in Kabul last year. The girls were allegedly exposed to a sweet-smelling gas that knocked them unconscious. At least six reportedly died.

In this week's poisonings, the Kabul government is saying that all affected students have recovered after hospital treatment. But rumors are circulating in Kabul that several students died.

"Whatever the truth, the government has been sufficiently concerned to come out with accounts blaming the 'servants of American imperialism' and giving political explanations," a regional analyst commented. "Whatever the actual cause of this, elements opposed to the government are trying to make whatever they can out of it."

In other Afghanistan developments, well informed sources report that residents of Herat, Kandahar and Mazar-i-Sharif have been on general strike since Saturday, and the Soviet officials and members of the rival Khalq and Parcham factions of the Ruling People's Democratic Party of Afghanistan are being assassinated in those cities "almost every night." Shootouts between members of the Khalq and Parcham wings were reported in Heart and Kandahar, both said to be under martial law.

Afghan Government officials denied that martial laws has been declared in those cities, Reuters reported. Radio Kabul, monitored by the British Broadcasting Corp., quoted a report by the official Bakhtar News Agency that false reports about Afghanistan were being spread by the U.S. government.

[It denounced a statement by State Department spokesman Hodding Carter III, who told reporters yesterday that Washington had received reports of martial law being imposed in the two cities.]

Travelers arriving in New Delhi today reported, in separate accounts, increasingly violent clashes between the two party factions. "They are like two crazy dogs," said one traveler, who added that five Parchamites had been killed several days ago at the Soviet-built Mikoyan housing complex. Four Soviet citizens, according to the travelers' report, were killed recently in the same area. One was reportedly hacked to pieces.

Another Traveler said the fighting between the two party factions is now more significant than the Babrak government's battle against the resistance fighters.

Meanwhile, Western diplomatic sources have discounted earlier reports of a massing of thousands of Afghan rebel fighters in the mountains outside Kabul for a major attack on the city.

The reports of a massive rebel influx are "purely imaginary," according to a diplomatic analyst. Acknowledging that "no one has an overall picture of what is happening," the analyst said there appears to be no major offensive in or around Kabul.