Polish Embassy taken in Berne

In the first guerrilla-style attack against Poland's martial law government since last December's military crackdown, a Polish group seized the Polish Embassy here Monday.

Identifying itself as the Revolutionary Patriotic Army of Poland, the group threatened to blow up the embassy, along with 13 hostages, within 48 hours unless military repression in Poland ended.

The group reportedly walked calmly into the embassy at 4:00 a.m. EDT. But four hours later, shots were reported fired; police gave no details on the shots or on the hostages taken. The group's statement transmitted to police said the embassy had been seized as a first step in protest against ''the declaration of war of the fascist regime of Poland of December 13, 1981'' - the date when martial law was declared. No connection was established between the attackers and the suspended Solidarity union movement, which has not advocated violence.

The message went on:

''We will leave the embassy and release all diplomats and employees, if:

1. Martial law in Poland is lifted;

2. All Polish political prisoners are released;

3. All prison camps are disbanded; and

4. The repression against the Polish people is stopped.''

Meanwhile, in Wroclaw, Poland, Solidarity leaders hailed last week's street demonstrations as a success and told workers in the area to prepare for a possible general strike. A clandestine bulletin also carried a statement by regional union officials calling on all workers in the Upper Silesia area to observe one minute of silence at noon Thursday to honor three people known to have died during clashes in that region last week.

The official Soviet news agency Tass said Foreign Minister Stefan Olszowski will fly to Moscow in the next few days for talks with the Soviet leadership.