NEW DELHI — A war crimes tribunal in Bangladesh on Sunday sentenced two expatriates — one now living in the United States and the other in Britain — to death by hanging for the murder of 18 people described as prominent intellectuals, during the country’s 1971 war of independence from Pakistan.

A verdict released in the capital, Dhaka, said the two men, who were tried in absentia, were guilty of “aiding, abetting, instructing, ordering, encouraging and providing moral support to” the killers of the 18 people, described as university professors, journalists and physicians, who supported the independence movement. The verdict said that the two men “had de facto reasonable material and authority to control” those responsible.

Both defendants fled Bangladesh shortly after it gained independence from Pakistan. One of the men, Chowdhury Mueen Uddin, settled in London, where he became a prominent Muslim leader, serving as a trustee for the charity Muslim Aid and as the director of Muslim Spiritual Care Provision in the National Health Service.

He has said that he rejects “each and every charge leveled against me,” and has refused to return to face trial because he did not expect a fair process.