Separatists Defy Russia in Caucasus : Soviet Union: Nationalists in Chechen-Ingush stand firm against troops sent by Yeltsin. The state of emergency is ignored by the secessionists.

In a potentially explosive showdown over their right to secede, militant nationalists in the mountainous, largely Muslim Chechen-Ingush region held their ground Saturday against Russian troop reinforcements and ignored the state of emergency decreed by Russian President Boris N. Yeltsin.

Thousands of civilians, meanwhile, poured into the streets of Grozny, the local capital, in support of Chechen independence from the Russian Federation--a move that Yeltsin and others fear could begin Russia’s unraveling after centuries of imperialist growth.

Several hundred internal security troops, airlifted into the Caucasus region to enforce Yeltsin’s control, reportedly met solid resistance both from local militiamen who seized the region’s airports and highways and from the thousands of people who blockaded the streets and converged on Grozny from the countryside.

The confrontation has forced Yeltsin for the first time to face the sort of virulent ethnic unrest that so diminished Soviet President Mikhail S. Gorbachev’s authority, and the Russian president’s decision to impose a state of emergency in the region Friday indicated his intention to be firmer.

“The Russian leadership has exhausted all opportunities for settling the situation in the Chechen-Ingush republic by political means,” Russian Vice President Alexander V. Rutskoi declared.

But Yeltsin’s decree, imposing a curfew and banning rallies to restore order and put down the Chechen nationalists, appeared to have had the opposite effect in helping mobilize the people to fight continued Russian rule.

Local officials said Chechen forces had captured hundreds of the Soviet internal security troops airlifted in to enforce the decree, although the Interior Ministry in Moscow denied it.

And the conflict spread to the air. Four hijackers who reportedly said they were protesting Russia’s intervention in Chechen affairs took over a Soviet TU-154 jetliner carrying 167 other passengers and seven crew members near the troubled region and forced it to land in Ankara, Turkey. News agencies reported from Ankara that after several hours the plane was refueled and allowed to return to the Soviet Union with all passengers aboard, including the hijackers.

Gen. Dzhokhar Dudayev, the Chechen strongman who has spearheaded the region’s secession movement and seized power a month ago, capped his defiance of the Russian leadership by taking his presidential oath Saturday--despite the Russian refusal to recognize his election victory as valid.

“We want to leave this totalitarian empire,” Dudayev said after the ceremony. The Chechen-Ingush republic declared its independence a week ago.

Masses of Chechens fired shots in the air to celebrate the inauguration, but there were no reports of injuries or deaths.

No matter what, Vice President Rutskoi told Russian television, “We will not allow bloodshed. Under no circumstances.”

Dudayev, a former bomber pilot in the Soviet air force, has declared Yeltsin’s state of emergency invalid and, in its place, imposed martial law, setting the stage for a head-to-head battle with the Russian leader.

In Moscow, several prominent politicians accused Yeltsin of Russian imperialism, but the Russian Parliament’s leadership backed their president’s move and called a special session for today to discuss the Chechen-Ingush crisis.

Rutskoi, speaking after the Parliament leadership met, accused Dudayev of violating his promises to obey Russian law and stressed that the Chechen-Ingush republic can secede only if it holds a referendum.

With only about 52% of the region’s 1.5 million people ethnic Chechens--most of the rest are Ingush and Russians--the pro-independence groups would find it difficult to gather the majority required for secession.

Although the Chechen region is far from Moscow and not strategically crucial, the push by Dudayev and members of his National Congress of the Chechen People for secession is proving an important test of Yeltsin’s will to fight for his belief that the Russian republic’s territory must remain intact.

With a vast territory that is home to 150 million people belonging to about 100 ethnic groups, the Russian Federation includes a score of “autonomous” regions set aside decades ago for particular nationalities.

Several other regions, Tatarstan in particular, are demanding independence from Russia, and others, such as diamond- and gold-rich Yakutia, insist on keeping the profits of their industries.

With all the trouble the autonomous regions are bringing, Moscow Mayor Gavriil Popov suggested Saturday that maybe “the nationalities should just live (lumped together) the way they do in the United States.”

Chechen-Ingush at a Glance Here are facts about the Chechen-Ingush Autonomous Republic: GEOGRAPHY: 7,350 square miles, about the size of New Jersey. POPULATION: Chechen and Ingush are ethnically related Turkic peoples, mainly Sunni Muslim, who speak Caucasian languages. About 52% of its 1.27 million people are Chechen, 12% Ingush and 29% Russian. ECONOMY: It contains a major Soviet oil field as well as chemical factories, food canneries, timber and furniture industry. HISTORY: Josef Stalin deported Chechen and Ingush to Kazakhstan and western Siberia in 1943 in retaliation for their uprising in World War II. They were allowed to return in 1957 and placed in a single autonomous republic, although they historically had separate lands. Chechen lived in tribal groups until Russia conquered them in late 1850s. During 1917-21 civil war, Chechen fought Cossacks and Bolsheviks. POLITICS: Since collapse of central Soviet authority after the attempted August coup, Chechen-Ingush republic has demanded more self-rule to avoid domination by Russian Federation. Gen. Dzhokar Dudayev was elected president of republic Oct. 27, but Boris N. Yeltsin called balloting fraudulent. Dudayev has declared a sovereign Chechen Republic and wants to secede from the Russian Federation, leaving the Ingush in a separate homeland.