MOSCOW, NOV. 13 -- Warning of a "bloodbath" if the Soviet Union breaks up, President Mikhail Gorbachev pledged today to preserve a unified economic system and a single army for the entire country.

Gorbachev's remarks, which were made to an unusual gathering of 1,100 military officers in Moscow, amounted to a direct warning to the country's restive republics against pushing their drive for national sovereignty too far and laid out the Kremlin's position on the division of power between Moscow and the country's 15 republics in final negotiations for a new treaty binding them together.

"To use a military expression, the union of sovereign republics represents our last trench line," Gorbachev told the officers, all elected officials in Soviet and local legislatures. "Beyond this lies the disintegration of the state."

Disillusioned by the failure of the central authorities to agree on a coherent economic reform package, several republics have effectively taken steps toward setting up their own economic and monetary systems.

In addition, the Ukraine and the three Baltic republics are insisting that their citizens perform military service only on their own territory in defiance of Soviet conscription regulations.

The president of the giant Russian republic, Boris Yeltsin, said today that Gorbachev had agreed "in principle" to the formation of a "coalition" central government that would include Russian ministers. But a Gorbachev spokesman said Gorbachev would not accept the resignation of the central government headed by Prime Minister Nikolai Ryzhkov, implying that the most he is prepared to concede is a shake-up of the present administration to include some Yeltsin nominees.

In a report to the Russian legislature, Yeltsin said he had told Gorbachev during a five-hour meeting last weekend that controversial questions over the control of natural resources, banking, taxation, budgets and foreign trade should be resolved before the conclusion of a new union treaty.

Yeltsin accused Gorbachev of concluding agreements with foreign countries, most recently with Germany, without consulting the Russian republic.

Last weekend's talks between Gorbachev and Yeltsin represented their first substantive encounter since August, when they seemed to have agreed in principle on a transition process from a centralized to a market economy.

But the understanding fell apart after Gorbachev sided with Ryzhkov on preserving many of the prerogatives of the central government, leading Yeltsin to accuse him of breaking his word.

Infuriated by what he called Gorbachev's "betrayal," Yeltsin last month raised the possibility of Russia's establishing its own currency and armed forces and pushing ahead with its own radical economic reform plans.

The more moderate tone of his most recent comments suggest that he is now looking for ways of working with Gorbachev, even though the two leaders are still far apart on key issues.

In his first public comments on last weekend's meeting, Gorbachev said today that he and Yeltsin did not disagree on the need to promote the sovereignty of the individual republics within the existing "federal" framework.

He added that he hoped a draft of a new union treaty could be submitted to the legislatures of the republics "within a week to 10 days."

During his meeting with the military officers, which lasted more than four hours, Gorbachev rejected calls by some republics for the formation of separate armies as a "political game."

"A united state must have a united army," he said, adding that the existing arrangements for integral military conscription from all over the Soviet Union should be preserved.

Discontent within the 4-million-member armed forces over poor living conditions and growing tensions in the country have fed a spate of recent rumors of a possible military coup attempt. Gorbachev dismissed the rumors, saying he had every confidence that the Soviet army "would realize its responsibility and side with the people."

Warning that any attempt to separate people who have "lived side by side for centuries" could "turn into a bloodbath," Gorbachev said the Soviet Union's unified economic system must be preserved.

He said economic breakup could lead to a situation worse than the 1966-76 Chinese Cultural Revolution, which plunged Communist China into chaos that left many thousands of people dead.

In practice, the Soviet economy is already disintegrating as individual republics and regions take whatever measures they can to protect the living standards of their own populations at a time of growing economic disorder.

The cities of Moscow and Leningrad this week announced plans to introduce full-scale rationing, effectively putting their stores out of bounds to Soviet citizens from other areas.