A day after assuming most of the powers of Slovakia's vacant presidency, Prime Minister Vladimir Meciar Tuesday canceled a referendum on seeking NATO membership and on holding direct elections for president.

Meciar's government also fired 28 ambassadors, the CTK news agency reported.The voting had been scheduled during the presidency of Michal Kovac, whose term ended Monday. A similar referendum collapsed last May when only 10 percent of voters turned out.

The Slovak constitution requires the prime minister to assume most presidential powers in the absence of a president. Twice this year, the divided parliament failed to muster the two-thirds majority needed to elect a new president. Another vote is set for Thursday.

Kovac, a political ally of Meciar when chosen president in March 1993, gradually became his most prominent opponent. Now, many of Kovac's powers pass to Meciar, who is the most popular politician in Slovakia. But Meciar also has many opponents who accuse him of totalitarian tendencies.

Last week, Kovac said he earned Meciar's enmity by refusing "to be an obedient tool in his hands."

Outside the presidential palace on Monday, a brass band played and Meciar and his Cabinet bid formal farewell to Kovac, while protesters shouted, "We don't want Meciar!"

Chants of "Thieves!" "Meciar is a dictator!" and "Meciar to jail!" echoed through the square.

As Meciar and his Cabinet swept into the palace courtyard in government limousines, a student, Mar-tin Kugla, addressed the pro-tes-ters.

"Here comes a man who believes he is Slovakia. We've come to show him majority of Slovaks don't think so," Kugla said.