DACCA, Pakistan, Nov. 6—Reliable sources here reported tonight that a United Nations vessel loaded with wheat intended for East Pakistani storm victims had been heavily damaged by a mine.

The Bengali Mukti Bahani guerrilla organization has been preying heavily on shipping in and to East Pakistan in recent weeks, but this was the first report that a clearly marked United Nations vessel had been attacked.

The boat, a “minibulker” used for carrying grain along East Pakistan's inland waterways, was reported mined Thursday night at the port of

Chandpur. Its cargo of 1,600 tons of wheat was in, the process of being transferred to other vessels.