Pakistan's opposition movement, hurt by numerous arrests and its identification with an airliner hijacking, failed to carry off planned massive protests against President Mohammed Zia ul-Haq's military government during the country's national holiday yesterday.

Zia, addressing a large audience at Rawalpindi's racetrack, declared that Pakistan's armed forces and 80 million citizens were ready to meet the situation created by "internal elements" and foreign enemies.

Police arrested an opposition leader as he began to denounce military rule before a relatively small crowd in Karachi. Another leader was detained before he could speak.

Pakistani observers said that the scheduled demonstrations drew little support because of a police crackdown which has led to the detention or house arrest of early all top officials of the opposition's Movement for the Restoration of Democracy and at least 350 political workers since early February.

Meanwhile, in Damascus, the Syrian government rejected a request by Zia for the extradition of the three Pakistani hijackers who seized a Pakistani airliner March 2 and held it 13 days.

Syrian authorities have jailed Craig Clymore, the freed American hijack hostage, while the United States presses for his extradition to face drug smuggling charges, American officials in Damascus said.