KARACHI, Pakistan, Sept. 19 —By‐elections for 78 National Assembly seats and 105 Provincial Assembly seats will be held in East Pakistan between Nov. 25 and Dec. 9, the Election Commission announced in Islamabad today.

The by‐elections are necessary because of the Government's disqualification of number of National and Provincial Assembly members who belong to the outlawed Awami League.

These Awami League members‐79 in the National Assembly and about 190 in the East Pakistan Provincial Assembly—lost their seats a few weeks ago after having been charged with criminal offenses. The commission announced that by‐elections for the remaining seats—one on the national level and more than 80 in the province— would be held later.

The League, led by Sheik Mujibur Rahman, won 167 of the 313 National Assembly seats, all from East Pakistan, in last December's general elections. Iin the Provincial Assembly it won 288 of 300 seats. The party was banned by President Agha Mohammad Yahya Khan in March when he ordered the armed forces to suppress the secessionist movement in the East.