Bangladesh police fired live rounds on Sunday afternoon in fierce clashes with thousands of Islamists, killing at least one and injuring dozens.

Violence reportedly broke out outside the Baitul Mukarram national mosque as a homemade bomb exploded when scores of Islamists engaged in scuffle with the law enforcers after facing police resistance towards a rally.

The Islamists under the banner of Hefazat-e-Islam kept marching towards the rally venue in Dhaka's commercial district Motijheel after they besieged the capital city for eight hours from morning to press home their 13-point demands which include mainly enactment of an anti-blasphemy law.

A Xinhua correspondent on the spot said clashes were still going on between the two sides when filing the report at about 4: 00 p.m. local time.

Parts of the capital Dhaka were turned into a battlefield as thousands of Islamists fought pitched battles with police and ruling party men with bricks and sticks in front of the national mosque and elsewhere in the city. Law enforcers retaliated with live rounds, rubber bullets and tear gas to quell the unruly protesters.

An emergency doctor at Dhaka medical college hospital who preferred to be unnamed told Xinhua that up to 30 people had been admitted, some with critical injuries from rubber bullets.

He said "one of the injured died of gunshot wounds." But the identity of the deceased could not be known immediately.

A Xinhua photo journalist said from Baitul Mukarram, "I've seen more than 50 bullet-shot people when they were rushed to hospitals. "

He said the sounds of a number of gunshots were still heard.

Dhaka remained virtually cut off from the rest of the Bangladesh as hundreds of thousands of Islamists besieged the capital city when long-distance buses plying between Dhaka and outlying Bangladesh places stayed off the roads from Sunday morning as the Islamists took position in six main entry points of Dhaka.

Leaders of Hefajat-e-Islam, a group of non-political Islamic scholars who draw support from thousands of people across Bangladesh, claimed nearly half a million people joined their activists of Dhaka to make the siege program a success.

Bangladeshi Prime Minister Sheikh Hasina urged Hefajat to call off the program from a press briefing on Friday evening while she gave assurance of meeting many of its 13-point demands.

Although she had earlier rejected Hefajat's demand for enacting an anti-blasphemy law stipulating punishment for defaming Islam and Prophet Muhammad.

The group has called the program apparently to gear up its ongoing campaign against the Shahbagh movement demanding capital punishment for war criminals and a ban on Bangladesh Jamaat-e- Islami party, many top leaders of which allegedly committed crimes against humanity during the country's nine-month liberation war in 1971.

Although the bloggers, some of whom reportedly spearheaded Bangladesh's Shahbag Square movement, have already denied the blasphemy allegations brought against them, the group, allegedly backed by Bangladesh-Jamaat-e-Islami party, has continued their movement, raising fears of a new round of violence.

The group said it demands restoration of the phrase "absolute faith and trust in the Almighty Allah" in the constitution, enactment of an anti-blasphemy law and punishment of "atheist bloggers."

Hefajat-e-Islam earlier on April 6 held a long march demanding punishment for the "atheist bloggers," several of whom have already been arrested.

Political tension in Bangladesh heightened in recent months as the 18-party opposition alliance, which have already dismissed the war crime tribunals as a government "show trial," geared up anti- government agitation programs, demanding restoration of a non- party caretaker government system to hold parliamentary elections slated for early 2014.

Former Prime Minister Khaleda Zia from a rally on Saturday slapped an ultimatum on the government to meet the opposition's demand for restoration of the caretaker government system within 48 hours.

Nearly 100 people, including several policemen and dozens of Jamaat leaders and activists, were killed and hundreds of others injured in the riots erupted since a tribunal awarded death sentence to the Jamaat's Vice President Delwar Hosssain Sayeede for war crimes in 1971 on Feb. 28.