Underground Solidarity leaders said Poland's martial law authorities are preparing show trials of the suspended labor union's leaders. A document made available to Western journalists, signed by seven fugitive Solidarity officials, also listed what it called human rights violations during the five months of martial law.
The document said: ''All indications are that a new danger has loomed over them (interned Solidarity leaders), that the groundwork is being laid for rigged trials modeled on those of the Stalinist period.''
Polish authorities have given no indication they are preparing to try the interned Solidarity officials for their role in leading the union.
A clandestine Solidarity radio broadcast, lasting 33 seconds before it was jammed, called for a 15-minute strike on Thursday. It would be the first general stoppage in Warsaw since the military takeover and a major act of defiance by workers against martial law. The radio also said all traffic should stop for one minute at noon and people should sound their car horns.