MOSCOW, JAN. 7 -- The Soviet Defense Ministry announced today that it is deploying thousands of crack troops to enforce presidential decrees against draft-dodging in seven Soviet republics where secessionist sentiment is running high.

The deployments come against a background of increasing political tension between the Kremlin and the country's 15 constituent republics, and President Mikhail Gorbachev has threatened to use his broad constitutional powers to maintain the integrity of the Soviet Union and its 4-million-member armed forces.

A Defense Ministry statement read on evening television news said that units would be sent to the three Baltic republics, Georgia, Armenia, Moldavia and parts of the Ukraine to help local military authorities round up deserters and draft-dodgers. Soviet generals have complained that less than a quarter of eligible conscripts responded to last year's fall draft in many of these regions.

Local reaction to the move is likely to vary from republic to republic. Baltic officials indicated that resistance there probably will be passive, but in the Transcaucasus region, where well armed vigilante groups control much of the countryside, there is the potential for violent confrontation and bloodshed.

In another move that underlined the Kremlin's get-tough policy, Gorbachev ordered Soviet Georgia's newly elected nationalist government to normalize relations with its Ossetian minority and gave the Georgian government five days to restore order in a region where there have been armed clashes between Georgian vigilante groups and Ossetian residents.

Today's developments are the clearest signal yet that Gorbachev intends to reassert his authority over rebellious republics by progressively tightening central control and rolling back provincial legislation that he considers in violation of the Soviet constitution.

Evidence of the new hard line has been accumulating over the past few weeks, beginning with the replacement of liberal interior minister Vadim Bakatin with former Latvian KGB chief Boris Pugo and a threatened military intervention in Moldavia that was forestalled only when the Moldavians backed down.

Addressing Soviet legislators last month, Gorbachev said he would not hesitate to order a state of emergency or impose direct presidential rule from Moscow on outlying regions in the event of "serious threats" to the Soviet Union's national security.

News of the troop deployments was revealed by the head of the Baltic military district, Gen. Fyodor Kuzmin, who telephoned the prime ministers of all three Baltic republics earlier today to inform them of the Defense Ministry order. Baltic officials quoted him as saying that the troops had orders to use firearms if they were met with resistance.

In a television address this evening, Latvian President Anatolijs Gorbunovs said Kuzmin had told him that an additional paratroop brigade -- numbering about 6,000 men -- was being deployed in the Baltic republics to enforce the draft. At least 100,000 Soviet soldiers and sailors are stationed in the Baltic military district, which stretches from Estonia in the north across Lativa and Lithuania to the Russian-controlled enclave of Kaliningrad on the Polish border.

Gorbunovs said he had reached an oral agreement with Kuzmin that the army would not take any action against draft-dodgers before next Sunday, to allow further negotiations between the army and local authorities. A similar moratorium appeared to be in force in neighboring Estonia, where an aide to President Arnold Ruutel said Kuzmin had offered to suspend the use of paratroops if local officials enforced the draft.

Annexed by the Soviet Union in 1940 under secret agreements with Nazi Germany, all three Baltic republics last year proclaimed the restoration of their prewar independence. They also passed laws allowing their citizens to perform alternative service in hospitals or social work rather than serve in the Soviet military.

The laws providing for alternative service have been declared invalid by the Kremlin, which insists that all Soviet males over the age of 17 are eligible to serve in the armed forces. Strictly interpreted, this means that at least 10,000 young Balts are considered draft dodgers or deserters by the Soviet high command.

In a statement, the Lithuanian leadership accused the Soviet Defense Ministry of planning to "violently kidnap" Lithuanian citizens and force them to serve in the Soviet military. It said that the Lithuanian republic, which declared its independence from the Soviet Union last year, would use "every political and legal means" to defend its citizens.

Baltic leaders attending a parliamentary conference in Helsinki said that today's moves appeared to be part of a broader political operation designed to halt the democratic process in the Soviet Union. They said that the Kremlin was hoping to take advantage of the world's preoccupation with the Persian Gulf by timing its domestic crackdown for around Jan. 15, the date set by the United Nations for Iraq to withdraw from Kuwait.

"All the world will be looking at the gulf and not looking at the Soviet Union," said Latvian Vice President Dainis Ivans, describing the deployment of paratroops as a step toward the introduction of a military regime throughout the country.

Tonight's Defense Ministry statement said that the "negligence" of local authorities in certain republics to enforce conscription regulations was undermining Soviet defense capability. It said that Georgia had only provided 10 percent of its annual quota for the military draft. Relevant figures for other republics were: Lithuania, 12.5 percent; Estonia, 24.5 percent; Latvia, 25 percent; Armenia, 28.1 percent; Moldavia, 58.9 percent.

The independent Soviet news agency Interfax reported tonight that violence had flared up again over the weekend in South Ossetia, an autonomous province of Georgia since 1922. It said that at least one person was killed in the Ossetian capital, Tskhinvali, after Georgian militia opened fire on civilians.

"Residents put up barricades across several streets in the center of Tskhinvali, using vehicles and reinforced concrete slabs. The town is practically divided," said Interfax, adding that a nighttime curfew was in force.

In his decree tonight, Gorbachev ordered the Georgian government to rescind its decision last month to suspend South Ossetia's autonomous status and expel vigilante groups from the area. Ossetian popular movements have called for secession from Georgia and reunification with north Ossetia, now a part of the Russian republic.

Georgian nationalists say they suspect the Kremlin of stirring up trouble among the 65,000 South Ossetians as a means of exerting pressure against them. The Ossetians are descendants of Indo-European tribes who have lived in the region since the 4th century.