Soviets Angry, Fearful Over Lithuania Clash : Protests: Thousands rally against what they say is a threat of dictatorship. More disapproval pours in from across Europe.

Fear and anger swept the Soviet Union on Sunday as people learned of the army’s bloody clash with Lithuanian nationalists, and thousands protested in rallies against what they called an impending dictatorship.

“We are witnessing the establishment of a dictatorship by the most reactionary circles of our society,” Yuri N. Afanasyev, a historian and radical member of the Congress of People’s Deputies, told a crowd of 3,000 gathered outside the Kremlin. “The dictatorship is being established under direction of the initiator of perestroika --as the dictator.”

Reaction from outside the country also came swiftly, news agencies reported. European nations condemned the crackdown, and Belgium’s foreign minister said that it could jeopardize a planned $1-billion European aid package. Officials of the North Atlantic Treaty Organization held an emergency meeting to discuss the situation.

In Brussels, Foreign Minister Jacques Poos of Luxembourg, which holds the rotating presidency of the 12-nation European Community, demanded an explanation from Soviet authorities, “notably (who) gave the order to fire at unarmed civilians.”

Foreign Minister Mark Eyskens of Belgium called for a meeting of European Community foreign ministers today and told Belgian radio about the possible suspension of the aid package.

Afanasyev’s statement here was a clear indictment of Soviet President Mikhail S. Gorbachev, who introduced the reform policy called perestroika, which brought the country political pluralism after decades of oppression.

Chanting “Today Lithuania, Tomorrow Russia!” “Freedom to Lithuania!” “Gorbachev resign!” and “Gorbachev is a Fascist!” the protesters marched through Red Square--many waving their Communist Party cards in the air.

“The actions taken under the order of the president in the Baltics are illegal and dangerous,” deputies to the Russian Federation Parliament said in a resolution read at the Moscow demonstration. “They prove the alarming message of Foreign Minister (Eduard A.) Shevardnadze.” Shevardnadze resigned Dec. 20, warning that a dictatorship was coming.

Protesters in Moscow held up signs that showed they held Gorbachev primarily responsible for the deaths in Vilnius: “Gorbachev is the Saddam Hussein of the Baltics!” and “Gorbachev is Today’s Hitler!” and “Gorbachev, Do Not Kill People in Lithuania!”

Protest rallies were held in Leningrad; Tbilisi, the capital of Georgia; Riga, the capital of Latvia; Kishinev, the capital of Moldova; Kiev, the capital of the Ukraine, and other cities to protest violence against civilians by Soviet troops seizing television and radio headquarters in Vilnius.

“Use of the army against civilians is the gravest of crimes, no matter what slogans are used to disguise it,” Sergei B. Stankevich, Moscow’s deputy mayor, told demonstrators. “We appeal to all soldiers who are citizens of Russia--don’t shoot at civilians. Russia does not allow you to do this.”

Russian President Boris N. Yeltsin, who met with leaders of the Baltic republics in Tallinn, the Estonian capital, also appealed to Russian soldiers to refuse their orders if sent against civilians.

“Violence in the Baltics will create a crisis in Russia,” Yeltsin said, according to the independent Baltic News Service. “By fulfilling orders, you are becoming a force in the hands of the dark reactionaries.”

The four republics--Russia, Lithuania, Estonia and Latvia--issued a joint statement denouncing the Red Army’s actions in Vilnius and emphasizing that it is “impermissible for their citizens to take part in military action against each other.”

In Estonia and Latvia, people were afraid they might be the next targets of Soviet troops.