Croatia's nationalist-dominated assembly took another step Thursday toward breaking from Yugoslavia, authorizing the republic to disregard federal statutes and providing parliamentary immunity to a minister the army says is plotting a rebellion.

On Wednesday, the parliament of the prosperous western republic of Slovenia's voted 173-1 to seek the breakup of the shaky Yugoslav federation that is dominated by Communist Serbia.The Slovenia body adopted a constitutional amendment declaring the supremacy of its own law over federal law and putting the republic on a path that President Milan Kucan said will end Yugoslavia as a single country.

The Croatian assembly voted overwhelmingly for an amendment to the republic's constitution providing the government of Croatian President Franjo Tudjman the authority to determine and nullify federal statutes it judges can endanger the republic's "interests and sovereignty."

The amendment prohibits federal authorities from imposing emergency measures or ordering military intervention in the republic during peacetime without the consent of Croatia's assembly or president.

"By this bill, the federal legal order ceases to be superior to the constitutional order of the Republic of Croatia," Vladimir Seks, an assembly vice president, told the legislature in the Croatian capital of Zagreb, 240 miles west of Belgrade.

The amendment took effect immediately.

Croatia and neighboring Slovenia, governed by nationalists who ousted communists last April in Yugoslavia's first free post-war elections, want to end the federal system, accusing Serbia's Marxists and their military allies of seeking political and economic control of the country.