Dhaka, Aug 22 - Bangladesh Prime Minister Sheikh Hasina has accused the previous government led by rival Khaleda Zia's Bangladesh Nationalist Party (BNP) of being 'involved in all grenade attacks' during its rule.

She made the accusation Friday as the nation observed the completion of five years of a grenade attack on her political rally Aug 21, 2004, investigations into which are still underway.

'Our government will bring to book all involved or behind-the-scenes instigators of the grenade attacks and killings. We will ensure their punishment, no matter how powerful they are,' Hasina was quoted as saying by the New Age newspaper.

She called upon her countrymen to be 'cautious and vigilant against all conspiracies'.

'If we remain united, we can free Bangladesh of murderers,' she said.

Hasina escaped the attack, when she was also fired upon, after being whisked away in a bullet-proof vehicle. But she nurses impairments in an eye and a ear.

Twenty-four people, including Ivy Rehman, wife of the country's current president Zillur Rahman, were killed and hundreds injured in the attack.

Hasina and her political associates say the case was sought to be misdirected.