Authorities in Bangladesh heightened security in the capital and elsewhere Saturday ahead of the expected execution of an Islamist party official sentenced to death for crimes against humanity during the country's 1971 independence war against Pakistan.

Mohammad Qamaruzzaman, an assistant secretary general of Jamaat-e-Islami, refused to seek presidential clemency, paving the way for him to become the second person put to death since tribunals were set up more than four years ago to try suspected war criminals.

Junior Home Minister Asaduzzman Khan told reporters that Qamaruzzaman would be hanged on Saturday.

Qamaruzzaman's family members visited him for the last time in Dhaka's Central Jail, with security tight outside the facility, his lawyer Shishir Manir said.

By Saturday evening, the concerned officials to execute Qamaruzzaman had entered the jail, a senior prison official told The Associated Press by phone on condition of anonymity because of the sensitivity of the issue.

TV stations reported that a grave had already been dug in Qamaruzzaman's ancestral home outside Dhaka, the capital.

On Monday, Bangladesh's Supreme Court rejected Qamaruzzaman's final legal appeal against the death sentence given to him by a special tribunal in May 2013. His only recourse would have been to seek a presidential pardon.

Bangladesh executed another Jamaat-e-Islami assistant secretary, Abdul Quader Mollah, in December 2013 for similar crimes.

Previous war crimes verdicts and Mollah's execution have sparked violence.

Prosecutors say Qamaruzzaman headed a militia group that collaborated with the Pakistani army in central Bangladesh in 1971 and was behind the killings of at least 120 unarmed farmers.

Bangladesh blames Pakistani soldiers and local collaborators for the deaths of 3 million people during the nine-month war seeking independence from Pakistan. An estimated 200,000 women were raped and about 10 million people were forced to take shelter in refugee camps in neighboring India.

Since 2010, two tribunals have convicted more than a dozen people, mostly senior leaders of the opposition Jamaat-e-Islami party, which had openly campaigned against independence. Jamaat-e-Islami, Bangladesh's largest political party, says the trials are politically motivated.

Prime Minister Sheikh Hasina set up the tribunals in 2010, reviving a stalled process and making good on a pledge she made before 2008 elections.

There was a process of trying suspected war criminals after Bangladesh gained independence, but it was halted following the assassination of then-President and independence leader Sheikh Mujibur Rahman — Hasina's father — and most of his family members in a 1975 military coup.