Thousands Flee Blasts in Soviet Pacific Port : Disaster: Explosion at Vladivostok arsenal triggers other blasts that thunder for hours across the city.

A blast Thursday at a large arsenal in a densely populated district of Russia’s Pacific port city of Vladivostok triggered thousands of other explosions, which thundered for hours and forced tens of thousands of people to flee their homes in fear for their lives, officials and local reporters said.

“It sounds and looks like the city has become the front in a war,” Igor A. Kots, a correspondent for the national Komsomolskaya Pravda newspaper, said by telephone from the scene. “People are panicking.”

The staccato sound of rapid explosions could still be heard in the background at midnight local time, 4 1/2 hours after the first explosion started a fire at the arsenal, a facility of the old Soviet Pacific Fleet and now part of the Russian military.

By 4 a.m. today, the explosions had stopped but the fire continued to rage, and the city’s entire military garrison was fighting the blaze, according to Valentin T. Novikov, an Interior Ministry official in Vladivostok.

Windows were knocked out of homes and factories nearby, and the ground shook as if from earth tremors, witnesses said. Thousands of residents carrying suitcases scurried from their houses to escape, Kots said. Two hospitals in the area were also evacuated.

More than 50,000 of the city’s 700,000 residents were evacuated, and four soldiers were wounded fighting the fire, Novikov added. No other injuries were reported.

This was the second such fire at an ammunition depot of the former Soviet military in recent weeks, raising fears that the breakup of the Soviet Union has shaken the military so deeply that it can no longer control its massive arms holdings. A month ago, a fire at an army ammunition depot in the Armenian town of Abovyan, northeast of Yerevan, the capital, set off explosions at the rate of 20 a minute and blazed for two days.

Officials at the headquarters of the joint armed forces of the Commonwealth of Independent States in Moscow confirmed reports of the Vladivostok fire but said they had no news about its cause or the extent of the damage. Novikov of the Interior Ministry also said the cause was unknown.

Kots said military officers at the scene had assured him that there were neither chemical nor nuclear weapons in the arsenal but that torpedoes, anti-submarine bombs and heavy artillery ammunition were stored there.

A year ago, local journalists wrote a series of articles exposing the potential danger of having an ammunition depot in a densely populated area and demanding that the military move it out of the area. The military responded by filing suit against the journalists, Kots said.

Vladivostok, the site of Russia’s largest port, was closed to foreigners until Jan. 1, when Russian President Boris N. Yeltsin opened the strategically located city and its port in hopes of helping Russia tap into the burgeoning Pacific Rim economic market.

Russian legislator Vladimir S. Lopatin, a Yeltsin adviser and fervent advocate of military reform, had lobbied to move the ammunition depot before the city was opened, according to Kots.