MOSCOW, JAN. 5 -- Russian President Boris Yeltsin today challenged Kremlin assertions that a provisional agreement had been reached on financing the Soviet Union's 1991 budget, despite some narrowing of differences between the republics.

"We are talking about a war of the budgets," Yeltsin told a group of reporters, adding that the central government could save more money by further reducing expenditure on the military. He said the Russian republic, which traditionally contributes more than half the federal budget, had made "enough concessions" to Moscow.

Yeltsin's comments today cast doubt on optimistic remarks earlier this week by Soviet President Mikhail Gorbachev, claiming that representatives of all 15 republics had reached agreement in principle on an emergency economic stabilization program. They suggest that the personal feud between the two most powerful politicians in the country is far from over.

As the largest and wealthiest republic, Russia holds the key to reaching a workable agreement on the budget. At a session of the full Soviet parliament last month, Gorbachev said a reduction in Russian contributions to the federal budget could result in economic chaos and the political disintegration of the country.

Yeltsin said today that the Soviet Finance Ministry is still demanding an additional 27 billion rubles from Russia during 1991, or around 6 percent of the annual federal budget. The federal government had earlier suggested that Russia was withholding 119 billion rubles, or about $20 billion. (There are a number of official exchange rates, but the most realistic is 6 rubles to the dollar.)

"We're not agreeing to give the last 27 billion, and we won't, since it directly contradicts our law," said Yeltsin, describing the request as "indecent" because he did not know how the money would be spent.

Yeltsin's comments contrasted with more upbeat remarks by Russian Information Minister Mikhail Poltoranin following Thursday's meeting of the Federation Council, which has the task of adjudicating disputes between the central government and the republics. Poltoranin did not dispute Gorbachev's assertion that a provisional agreement had been reached on how to finance the budget.

Yeltsin, who is consistently ranked in opinion polls as the most popular politician in the country, denied charges by Gorbachev that Russia was undermining the Soviet Union. Yeltsin said Russia is in favor of signing an agreement on stabilizing the country's economic situation, but had historically borne too great a share of the federal budget, subsidizing other republics. He said Russia submitted an alternative draft agreement to Gorbachev today.

Asked about the military budget, Yeltsin said Russia is willing to bear expenses related to the social needs of service members and their demobilization. But he said cuts could be made in the portion of the budget earmarked for technical procurement and research and development.

In a new presidential decree on economic reform, meanwhile, Gorbachev tonight called for inventories to be drawn up of unproductive state farms so their land could be distributed to private farmers. The decree calls for between 7 million and 12 million acres of state-owned land -- less than 1 percent of the total -- to be redistributed by spring.