Police in Bangladesh have charged seven people, including a senior opposition official, over the murder of an Italian aid worker last September, an officer has said.

Cesare Tavella, 50, was shot dead by motorcycle-riding assailants in September 2015 while jogging in the diplomatic quarter of Dhaka, Bangladesh's capital.

Bangladesh religious leaders issue 'fatwa' against violent attacks

The killing was the first in a wave of attacks in Bangladesh to be claimed by the Islamic State of Iraq and the Levant (ISIL, also known as ISIS) group.

Yet, the secular government of Sheikh Hasina denies the involvement of ISIL, saying the armed group has no presence in the country.

Instead, authorities say the deaths are part of a plot to destabilise the country and have blamed homegrown groups and the main opposition Bangladesh Nationalist Party (BNP).

Deputy commissioner of Dhaka Metropolitan Police Sheikh Nazmul Alam said on Tuesday that seven people had been charged with the murder of Tavella, including two BNP officials.

"We submitted the charge sheet against the seven on Monday. Those who are charged include Abdul Quayum, who masterminded the attack," Alam told the AFP news agency, referring to a senior BNP official who is believed to be living in exile in Malaysia.

He said that the attack was part of a plot "to tarnish the image of the country and destabilise it".

Quayum denied the charge, telling the Daily Star newspaper that he was being victimised because of his political affiliation.

BNP spokesman Ruhul Kabir Rizvi said that the charge was "false and politically motivated".

"It is an attempt to hide the real killers," Rizvi told AFP.

READ MORE: Bangladesh arrests thousands after series or murders

Dozens of foreign aid workers, atheist bloggers, liberal academics, gay rights campaigners, members of minority Muslim sects and other religious groups have been killed in brutal attacks across Bangladesh in recent years.

Earlier this month, the government launched a nationwide crackdown on local groups, arresting more than 11,000 people, under pressure to act on the spate of killings.

But many rights groups allege the arrests were arbitrary or were a way to silence political opponents of the government.

Source: Agencies