"The government is conspiring to kill Jamaat-e-Islami's Ameer (chief) Motiur Rahman Nizami in a planned way (and) to implement the plan, it arranged the farce of a trial with false and fabricated allegations," Jamaat said in a statement.
A special tribunal in the southeastern port city of Chittagong handed down the death penalty on Thursday to Nizami, who was industries minister in a previous BNP-led coalition government, Barua and 12 others for involvement in Bangladesh's biggest ever weapon haul in 2004.
The Jamaat's announcement triggered fears of fresh political violence in the country, which witnessed a prolonged spell of strikes and blockades enforced by an opposition alliance of which the Jamaat is a member. The unrest had subsided after the January 2 polls, which was boycotted by the opposition.
Besides the Jamaat chief, Bangladesh Nationalist Party (BNP) leader and former minister Lutfozzaman Babar and two retired army generals who headed intelligence agencies were also sentenced to death. The main opposition BNP described the tribunal's verdict as a "deep conspiracy" to ruin it.
Those who recovered the weapons during the tenure of the then BNP-led government were put on trial, it said. "It's a part of conspiracy to root out the party," BNP leader Ruhul Kabir Rizvi said.
Barua, a fugitive, was given the death sentence in absentia. He now leads a faction of the banned United Liberation Front of Asom (ULFA) opposed to talks with the Indian government. ULFA for long has had bases and business interests in the Chittagong area.
Around 1,500 boxes containing submachine guns, AK-47 assault rifles, submachine carbines, Chinese pistols, 840 rocket launchers, 27,000 grenades and 11.41 million bullets were seized from 10 trucks in the early hours of April 2, 2004.