Several thousand workers from Yugoslavia's largest rubber and shoe plant Wednesday forced their way inside the Federal Parliament building, but police forced them out a half hour later, witnesses and the Tanjug news agency said.

In an action unprecedented in Communist Yugoslavia's postwar history, about 4,000 demonstrators clashed with security police in front of the Parliament building. Police were unable to stop the protestors from entering.The workers are demanding a 100 percent pay increase, 30 percent reduction of the plant's administration, better working conditions and full rather than partial payment of June wages.

The workers said their average wages amount to 150,000 dinars, or $62.50. The average Yugoslav salary is the equivalent of $120 per month.

The demonstrators filled the halls of the domed classical-style building, demanding negotiations with top government officials and chanting slogans calling for changes in the leadership.

After about half an hour, police and Parliament security officers forced them to leave. No weapons were used and no injuries were reported, Tanjug and witnesses said.

Tanjug said the demonstrators waited outside the building for the president of Parliament, Dusan Popovski, to come out and address them.

The demonstrators demanded the resignation of Nenad Krekic, Yugoslavia's finance minister. Krekic was the director of their plant two years ago and the workers hold him responsible for their situation.

About 5,000 demonstrators, representing about 10,000 strikers of the Borovo plant, traveled on foot and by bus from Borovo, a central Yugoslav town 62 miles west of Belgrade. They began arriving in the capital during the night and continued coming during the morning.

The demonstrators were met at a downtown trade union building by a government delegation that included Zvonimir Hrabar, state trade union president; and Spasoje Medenica, vice president of the Federal Parliament.

"They promised us everything except the pay hike which is our main demand," one Borovo worker, Zorica Radic, told The Associated Press.

"We refuse to move from here and will continue the protest until our demands are met," she said.

More than 10,000 people, mostly Borovo workers, demonstrated Tuesday in Vukovar, the administrative center of the region about three miles south of Borovo. They chanted "Down With the Government" and demanded higher wages, witnesses said.

The demand for pay increases clashes with the government's austerity measures that link wages to productivity in order to cut inflation, currently at about 175 percent, and to improve overall economic performance.

Yugoslav officials claim there is no alternative to the program, made in conjunction with the International Monetary Fund, if the country wants to pay off its $21 billion foreign debt.

"How can we survive and do heavy physical work if the prices go up and the wages are the same level or even go down?" one of the workers who arrived in Belgrade said.

"We will not continue to work and there will be a lot of trouble if our wages are not hiked," he said.

Another 2,000 workers of the Vertilen textile factory in Varazdin, about 30 miles north of Zagreb, also were on strike.

They marched on the town's streets Wednesday chanting "We Want Bread and Work," and demanded that the factory, temporarily closed for producing losses, be reopened.