Rawalpindi. Sept 28— The Pakistan Government announced today that 20 prosecution witnesses had been heard in the secret trial before a military tribunal of Shaikh Mujibur Rahman, the East Bengal leader.

A statement from the office of President Yahya Khan said that the trial had resumed on September 7. It was the first official word on the proceedings since August 21 when it was announced that a leading Karachi lawyer, Mr Allah-bux Brohi, had agreed to defend Shaikh Mujibur.

Speculation has been mounting in the Pakistan press that the Shaikh may be released, but today’s announcement contained a warning against all comment which might prejudice the case.

The Pakistan Government radio claimed today that its Navy had killed 10 frogmen and captured three others, who said they were trained by Indians to mine ships in Chittagong and Chalna harbours in East Pakistan.- AP.