ISLAMABAD: Pakistan Foreign Office on Wednesday said it was deeply saddened over the hanging of the Jamaat-i-Islami Bangladesh chief Motiur Rahman Nizami after a decision by a controversial war crimes tribunal for his involvement in 1971 events, media sources said.

“The act of suppressing the opposition by killing their leaders through flawed trials is completely against the spirit of democracy,” Foreign Office spokesman Nafees Zakaria said in a statement.

The statement said it is “unfortunate” for the people of Bangladesh who had elected Nizami as their representative in the Parliament.

Clashes erupted in Bangladesh Wednesday after Nizami’s execution, heightening tension in a country reeling from a string of killings of secular and liberal activists.

Nizami was hanged at a Dhaka jail late Tuesday for the massacre of intellectuals during the 1971 independence war with Pakistan.

Police said they fired rubber bullets after hundreds of Nizami’s supporters attacked them with stones in the northwestern city of Rajshahi.

“There were 500 Jamaat activists who were protesting the execution. We fired rubber bullets as they became violent,” Rajshahi police inspector Selim Badsah told AFP, adding that about 20 were arrested.

Jamaat and ruling party supporters also clashed in Chittagong, where about 2,500 pro-Jamaat activists attended a service for the executed leader, the port city’s deputy police chief Masudul Hasan said.

Security was tight across the country, with checkpoints erected on main roads in Dhaka to deter violence, and thousands of police patrolling the capital.

Nizami, a 73-year-old former government minister, was the fifth and the most senior opposition figure executed since the government set up a controversial war crimes tribunal in 2010.

Security was also stepped up in Nizami’s ancestral district of Pabna, where his body was taken under armed escort for burial in his family’s grave.

“At least 16 activists of Jamaat were arrested (in Pabna) Tuesday night as part of the security clampdown,” local police inspector Ahsanul Haq said.

Jamaat called a nationwide strike for Thursday in protest at Nizami’s execution, saying the charges against him were false and aimed at eliminating the party’s leadership.

Executions of Jamaat officials in 2013 triggered the country’s deadliest violence in decades. Around 500 people were killed, mainly in clashes between protesters and police.

But a fresh wave of bloodshed is considered unlikely following a major crackdown by Prime Minister Sheikh Hasina’s government that has seen tens of thousands of Jamaat supporters detained.

Secular protesters cheered the midnight hanging, with hundreds gathered outside the jail and at a square in central Dhaka overnight to celebrate what they described as an historic moment.

Mubashar Hasan, an assistant professor at Bangladesh’s University of Liberal Arts, said Tuesday’s execution may sound the death knell for the already embattled Jamaat.

“With the execution of Nizami, the Jamaat leadership who revived the fortune of the party in the post-1971 period are now almost gone,” he said.