Dhaka, Feb 4 (IANS): Bangladesh Nationalist Party (BNP) chief Khaleda Zia has been accused by police of "instigating" Tuesday's arson attack on a bus in Comilla district which left seven people dead, a media report said Wednesday.

Former Comilla member of parliament (MP) and Jamaat-e-Islami leader Syed Abdullah Mohammad Taher has also been accused in the case, bdnews24.com quoted Tutul Charkavarty, the district's superintendent of police, as saying.

According to reports, the attack on the bus also left 16 people injured, three of them critically.

A total of 56 BNP and Jamaat activists have been accused in the attack, a police official said.

Bomb and arson attacks on vehicles during the BNP-sponsored countrywide blockade since Jan 5 have claimed over 50 lives so far.

Zia, the former Bangladesh prime minister, called the blockade Jan 5 when police barred her from leaving the party office to lead the anti-government agitation.

The BNP-led opposition alliance had boycotted the general election held last year in January.

Zia's 20-party opposition alliance has been enforcing a blockade across the country, demanding fresh elections under a non-party caretaker government.

Zia has already been named as the instigator in two earlier incidents of arson.

She, however, has refused to call off the blockade despite repeated requests.