TALLINN, USSR — Hundreds of thousands of Estonians, Latvians and Lithuanians linked hands in a 370-mile human chain across their nations Wednesday evening in a solemn display of their dream of independence from the Soviet Union.
The chain of humanity began in Tallinn in Estonia, on the Gulf of Finland. It stretched south and west through forests, farmland and villages to Vilnius in Lithuania, joining men, women and children, many of them dressed in their national colors and waving the flags of the Baltic nations.
No immediate estimate of the throng was available, but reports from the three nations indicated that it easily surpassed earlier hopes of 700,000 and may have been substantially more than 1 million-out of a Baltic population of barely 9 million.
The chain began at 7 o`clock on a cool, clear evening and lasted barely 30 minutes. In many towns, rallies followed.
``The whole world is watching us,`` Estonian Popular Front leader Marju Lauristin said as the chain began. ``It sees that our nations live and have not surrendered.`` Her words were carried along the chain by thousands of transistor radios.
The occasion was the 50th anniversary of the Molotov-Ribbentrop Pact, the infamous 1939 treaty between Nazi Germany and Stalin`s Soviet Union that secretly divided Eastern Europe into spheres of influence.
The so-called ``nonaggression`` pact set the stage for forcing the three Baltic nations a year later into the Soviet Union, which formally considers them constituent republics of the USSR.
The USSR now admits that the treaty`s secret protocols, long denied by Moscow, are genuine. And in little more than one year, the debate over the pact has led to a fast-growing Baltic independence movement uniting dissidents and Communist Party leaders.
``We`ve become free within ourselves. Now must come the point where the whole nation becoms free,`` said Mikk Titma, the ideological chief of Estonia`s Communist Party. He spoke from Tall Hermann, a 14th Century landmark tower in Tallinn where the human chain began.
``We are not alone,`` said Lagle Parek of the Independence Party, which organized a rally, attended by thousands, in a park at the base of Tall Hermann before the chain formed. ``All three Baltic nations are together. We demand freedom for ourselves!``
The blue, black and white Estonian flag flew from the top of Tall Hermann and from thousands of hands along the chain.
Independence Party members wore signs-``USSR Go Home``-around their necks. Others wore black buttons reading ``International Day of Mourning.``
The mood was somber but determined. Despite the emotion of the occasion, few people cried.
Leaders of Baltic popular movements issued a statement demanding the right to ``restore their independent statehood.`` The statement said the USSR ``infringed on the historical right of the Baltic nations to self-determination, presented ruthless ultimatums to the Baltic republics, occupied them with overwhelming military force, and under conditions of military occupation and heavy political terror carried out their violent annexations.``
In Vilnius, about 5,000 people gathered in Cathedral Square, holding candles and singing Lithuania`s national anthem.
In Riga, Latvia, men, women and children sang the Latvian national anthem, then stood peacefully for 15 minutes with arms linked in a dramatic show of nationalist feeling.
In Moscow, ranks of special riot police waving clubs and backed by water cannon broke up a small but raucous sympathy demonstration by a few hundred people. The Tass news agency said 75 people were detained for breaches of the peace and other offenses.
Coordination of the chain, a formidable task organized by Popular Front movements in the three states, was helped by the cooperation of government-controlled radio, which broadcast instructions and a stream of patriotic songs, anthems, poems and speeches.
There was no reported violence, even though Russian groups living in Estonia denounced the chain as a ``provocation.`` Many of them have just ended a strike to protest alleged anti-Russian discrimination, and Estonian leaders said the strike gave the Estonians new unity.
After the chain was formed, a poem broadcast over the radio ended with the word ``Freedom`` repeated again and again, ever louder, chanted in unison along the 130-mile stretch of the chain through Estonia.
A male choir sang Estonian folk songs and a pop singer, Tonis Magi, sang a new song: ``God save Estonia, God save the Land of St. Mary. Freedom is dawning.``
The pre-chain rally included speeches by the Independence Party, the Estonian Christian Society and the new Green Party and a letter from Sen. Don Riegle (D., Mich.) read in Estonian. In a nation where dissent has alway been difficult and public dissent unthinkable, the speeches and signs were a vivid display of the strides made in the last year or two.
``The occupation still goes on,`` read one sign, emblazoned with the Nazi swastika and Soviet hammer and sickle.